Liknayan, Pagpupugay, at Paalam

“KASAGUTAN”

ni Lalaine Denise C. Cardenas

Sa mga bituing nagniningning sa kalangitan, mapapatanong ka na lang kung saan ang kanyang pinanggalingan. ✨

Sa mga alon sa katubigan, mapapaisip ka na lang kung anong laman. 🌊

Sa mga ilaw sa loob ng tahanan, magdududa kung sinong may gawa.💡

Sa mga bolang hinagis pataas, paano kaya ito babalik sa lupa?🏀

Sa mga pormulang ibinigay, saan ito napulot?➕

Sa lahat ng bagay dito sa paligid, sinong makakapagpaliwanag?🌳

 

Ang gunam-gunam ng mga tao ay walang hangan,❓

Ang mga hinuha ay may patutunguhan,🤔

Ang mga kathang-isip ay maipapaliwanag,🦄

Ang mga kinatatakutan ay magiging kaibigan.👻

Lahat ng bagay ay kayang matuklasan, maipaliwanag, at mahanap ang kahulugan.📜

Ito ay maabot sa pamamagitan ng Pisika;

Ang karunungan tungkol sa likás ng mga bagay ng katalagahan.😎

 

Simula sa pagtuklas sa pinakamaliit na bagay sa mundo,🐜

Sa mga elemto sa paligid;⚡

Sa hinagis na bumalik;⚽

Sa mga pinapalipad;✈

Sa mga ilaw sa kalangitan;🌟

Sa pagkalikha ng mga nakakabilib na mga kagamitan;📱

Sa pagtunghay ng nakaraan, kasalukuyan, at kinabukasan;😮

Lahat ay dahil sa kanyang karunungan.🧠

 

Hindi maipagkakaila ang pagiging ignorante sa mga bagay.👶

Mapapatanong sa lahat, kung paano ba ito nilikha🤷‍♂️

Kung anong nangyayari sa loob,🔏

Paano nangyari iyan?🤔

Saan nanggaling ang mga ‘yan?😲

Anong laman ng ganyan?🤪

Hoy! Paano? Kailan? Saan? Ano? Bakit?😇

 

Subalit ika’y nariyan.😍

Iyong niliwanagan ang isipan.☀

Iyong binigyan ng kasagutan.🗯

Binigyan mo ng sulosyon.➖

Binigyan mo ng dahilan.🌸

Sa lahat ng tanong, ay mabibiyan mo ng kasagutan.

 

Isa kang pagsubok ng kapwa ko mag-aaral.🤐

Mabigat kung buhatin subalit kakayanin.🙃

Kahit hindi na kayanin ng isipan ay lalaban parin! (awwwe)

Kahit wala ng ganang pumasok, ikaw ay papasukin parin! 💦

Sapagkat katanungan namin ay kaya mong sagutin.

 

Subalit, kami’y magtatapos na, (saaad)

Ang pasasamahan natin ay mawawala. (aww)

Pero mananatili parin, (yiee)

Mga aral na iyong ibinigay, 💕

Mga kasagutan sa mga tanong,❤

Mga solusyon sa mga bagay-bagay.👍

Ika’y naging sandalan at kahit anong mangyari ika’y mananatili sa puso’t isipinan. (AYIEEE)

 

Salamat sa lahat lahat-lahat. 😥

Pisika na naging bahagi ng buhay ko. 😎

Simula sa pagkabata hanggang sa aking pagtanda, 👵

Sa aking paglalayag ay mananatili ang mga katagang tumatak sa akin.🗝

Na kahit na anong mangyari ay mabibigyan ito ng kasagutan.👀

Salamat at paalam.👋

It Reflects

Hello everyone! Welcome to my new blog! Today we will discuss the things about the law of reflection, multiple reflections, image formation on plane mirrors, image formation on curved mirrors (concave and convex), the mirror equation , and practical uses of the different types of mirrors. Wew! That was a lot. I will do my best to briefly discuss these topics for you! Enjoy 🤗🤞

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What I know

Honestly, I do not know anything about these topics. I simply thought that there are different kinds of mirrors that’s why it creates different kinds of images. But I do not know anything further about these things.

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What I Learned

There’s no turning back let’s now begin. 😍

The Law of Reflection ✨

The law of reflection governs the reflection of light-rays off smooth conducting surfaces, such as polished metal or metal-coated glass mirrors.

The law of reflection states that:

“The incident ray, the reflected ray, and the normal to the surface of the mirror all lie in the same plane.”

Furthermore, the angle of reflection  is equal to the angle of incidence . Both angles are measured with respect to the normal to the mirror.

The law of reflection also holds for non-plane mirrors, provided that the normal at any point on the mirror is understood to be the outward pointing normal to the local tangent plane of the mirror at that point. For rough surfaces, the law of reflection remains valid.

Mirrors reflecting other mirrors ⚡

If you place two mirrors at an angle, you increase the number of reflected images you can see. Depending on the angle you choose, you can see a number of unbroken reflections and one or more composite or partial reflections. When the mirrors are set at 90º and 60° degrees exactly, the composite reflection is evenly divided so it looks like a single image.

The angles of incidence and reflection

Without going into exquisite detail, what you see also depends on where you stand and where you place the object – the angles of incidence and reflection.

If the reflected rays are extended backward behind the mirror (see dashed lines), they seem to originate from point QQ. This is where the image of point PP is located.By forming images of all points of the object, we obtain an upright image of the object behind the mirror.

There are two types of image form in mirrors here are the following:

1. Virtual Image

The image behind the mirror is called a virtual image because it cannot be projected onto a screen—the rays only appear to originate from a common point behind the mirror. If you walk behind the mirror, you cannot see the image, because the rays do not go there. However, in front of the mirror, the rays behave exactly as if they come from behind the mirror, so that is where the virtual image is located.

2. Real Image

A real image can be projected onto a screen because the rays physically go through the image. You can certainly see both real and virtual images. The difference is that a virtual image cannot be projected onto a screen, whereas a real image can.

Locating an Image in a Plane Mirror 💕

The law of reflection tells us that the angle of incidence is the same as the angle of reflection.

If we measure distances from the mirror, then the object and image are in opposite directions, so for a plane mirror, the object and image distances should have the opposite signs: do=−di.

Multiple Images😚

If an object is situated in front of two mirrors, you may see images in both mirrors. In addition, the image in the first mirror may act as an object for the second mirror, so the second mirror may form an image of the image. If the mirrors are placed parallel to each other and the object is placed at a point other than the midpoint between them, then this process of image-of-an-image continues without end, as you may have noticed when standing in a hallway with mirrors on each side.

Thus, the fronts and backs of images 1 and 2 are both inverted with respect to the object, and the front and back of image 3 is inverted with respect to image 2, which is the object for image 3.

You may have noticed that image 3 is smaller than the object, whereas images 1 and 2 are the same size as the object. The ratio of the image height with respect to the object height is called magnification.

Parts of a Mirror

To more understand the concave and convex mirrors, the following must be mastered:

Image Characteristics for Concave Mirrors 😊

Case 1: The object is located beyond C                           Case 2: The object is located at C

                                                                              

Case 3: The object is located between C and F            Case 4: The object is located at F

                                                                              

Case 5: The object is located in front of F

Image Characteristics for Convex Mirrors 👊

According to the graphical method, the image produced by a convex mirror can always be located by drawing a ray diagram according to four simple rules:

1. An incident ray which is parallel to the principal axis is reflected as if it came from the virtual focus of the mirror.
2. An incident ray which is directed towards the virtual focus of the mirror is reflected parallel to the principal axis.
3. An incident ray which is directed towards the centre of curvature of the mirror is reflected back along its own path (since it is normally incident on the mirror).
4. An incident ray which strikes the mirror at its vertex is reflected such that its angle of incidence with respect to the principal axis is equal to its angle of reflection.

The validity of these rules in the paraxial approximation is, again, fairly self-evident.

In the example shown in figure, two rays are used to locate the image  of an object  placed in front of the mirror. It can be seen that the image is virtual, upright, and diminished.

 

The Mirror Equation

The mirror equation expresses the quantitative relationship between the object distance (d_o), the image distance (d_i), and the focal length (f). The equation is stated as follows:

The magnification equation relates the ratio of the image distance and object distance to the ratio of the image height (h_i) and object height (h_o). The magnification equation is stated as follows:

These two equations can be combined to yield information about the image distance and image height if the object distance, object height, and focal length are known.

Practical uses of the different types of mirrors 💖

The three most common mirror glass types for home decor are:

• Plane Mirror — These are flat mirrors that reflect images in their normal proportions, reversed from left to right. This is the most common type of mirror used in bedrooms and bathrooms.
• Concave Mirror — Concave mirrors are spherical mirrors that curve inward like a spoon. They create the illusion of largeness and are typically found in bathrooms and bedrooms.

Convex Mirror — Convex mirrors are also spherical mirrors. However, unlike concave mirrors, they bulge out and distort the reflected image, making it small

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How I Learned

To attain these knowledge the following are the things I’ve done, try it maybe it’s effective 😉

Activities/Experiments

The activities really help me to more understand this topic, I somewhat love this way for me to more become independent in so many ways. Our teacher, Mr. Supnet, challenge us to become more productive in our own ways.

Discussions

It really helps us, the words of wisdom created by our teacher. It was fun tho, the technique he uses. It is quite different that the other teachers, maybe that’s why we learn a lot in this subject.

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Reflection 🤣

In our daily lives we see our reflection anywhere and it is part of our lives. Sometimes it reflects its true image but some mirrors doesn’t. It reflects us. It is us. No matter what it we should accept it whole heartedly.

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Bibliography

Reflection. Retrieved at https://www.physicsclassroom.com/class/refln/Lesson-3/Reflection-of-Light-and-Image-Formation

Characteristics of Concave mirrors. Retrieved at https://www.physicsclassroom.com/class/refln/Lesson-3/Image-Characteristics-for-Concave-Mirrors

Mirror Equation. Retrieved at https://www.physicsclassroom.com/class/refln/Lesson-3/The-Mirror-Equation

Common types of mirrors. Retrieved at https://glassdoctor.com/content/types-of-mirrors

 

BATO BALANI

Yohooo! What’s up? Well, this is going to be my first blog for the fourth quarter, second semester. And the lesson for today is about Electromagnetism! Yeyy! 👏👏 Now, scroll down and see the ideas I knew before the discussions, the lessons I learned from the discussions and activities, how I obtained these learning and lastly, my realizations after the discussions. Enjoy! 😁

Preliminary Knowledge 👶

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Electromagnetism is such a wonderful knowledge a man discovered. But honestly, I don’t remember any lessons about electromagnetism. I don’t have enough knowledge about this lesson but I’ll try my best to survive this grading. 😁🤣

What I Learned… 👩‍🏫

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What is Electromagnetism? 🤷‍♂️

Electromagnetism deals with the relationship between electricity and magnetism.

Electromagnetism is also fundamental physical force that is responsible for interactions between charged particles which occur because of their charge and for the emission and absorption of photons, that is about a hundredth the strength of the strong force, and that extends over infinite distances but is dominant over atomic and molecular distances–called also electromagnetic force

What is Magnetism? ❤

• The ability of a magnetic material, lodestone for instance, to attract other magnetic substances. A material with this kind of ability is called a magnet.
• Another definition of Magnetism is a class of  physical phenomena that are mediated by magnetic fields.

A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.

Classification of magnets 💖

Natural (found in nature)
Lodestones or magnetite are common examples of natural magnets. They are also used to create magnets, artificial ones, by magnetizing them through stroking a magnetic material with a magnet, by electric current and by induction from Earth’s magnetism.

 

Artificial (temporary or permanent)

Artificial magnets can be temporary or permanent, it just depends on the material’s retentivity– the ability to retain its magnetism after it has been magnetized.Artificial magnets can come in various shapes. Common shapes are bar magnet, horseshoe magnet and ring magnet.

 

Types of Magnetism 💕

1. Ferromagnetic Materials– they are strongly attracted by magnets and can make a strong permanent magnet but when heating at a certain temperature, it can lose its magnetism, that temperature is call the Curie temperature. Iron, cobalt, nickel and steel are common examples of this type.
2. Paramagnetic Materials– they are weakly attracted to magnets and when cooled, they become more magnetic. Palladium, platinum and the transitional metals are examples of this type.
3. Diagmanetism– is a weak response to magnetic field. Instead of being attracted, they are repelled by the magnetic field. Examples are water, silver, gold, lead and other organic compounds.

Earth has it’s own magnetism, it is called Geomagnetism.  Earth can act as a huge magnet with its north and south magnetic poles.

Peregrinus Proteus discovered that like poles repel and unlike poles attract. In line with that, in 1785, Charles de Coulomb proposed that the force between poles is similar to the force of attraction or repulsion between electric charges.

The force of attraction and repulsion between two poles is given by the formula:

where k= 10-7 N/A2, F is the force in N, m1 and m2 are the pole strengths in Am, and d is the distance between poles.

The concept of magnetic field 🤗

A magnetic field is a space where a a magnetic material could experience the force of the magnet.  Its strength can be defined into two ways, (1) is by magnetic flux and (2) is by the force exerted on an electric charge moving in the field. It is shown by this formula:

The direction of a magnetic field is the direction in which a north pole will move when placed in that field. For example, if a compass is placed in a magnetic field, the compass will point in the direction of the field.

Magnetic field is made up of lines of force that emerge from North to South Pole. The number of lines of force is called the magnetic flux. The SI unit of flux is Weber and the flux per unit area is called the magnetic field or the magnetic field intensity in the SI unit tesla named after Nikola Tesla. It is in this formula:

When finding the amount of a magnetic flux passing through a surface, this formula can be used:

Electromagnetic Induction 😍

The production of electromotive force or emf. It can also be described as the production of electric current across a conductor when exposed to a changing magnetic field. And the produced current and emf are called induced current and induced emf.

There are two laws governing electromagnetic induction and these are the Faraday’s Law  and Lenz’s Law:

Faraday’s Law states that “whenever there is a change in a magnetic flux in a circuit, an induced current is produced.” Which makes the rate of change in magnetic flux proportional to the induced current.

Lenz’s Law states that “the induced current flows in a direction so as to oppose the change causing it.”

If Faraday and Lenz’s law are combined, the formula would be:

where E is the induce emf, N is the number of turns of the coil, Δɸ  is the change in magnetic flux and is equal to ɸfinal – ɸinitial, Δt is the time elapsed.

The relationship of each variables 🤔

1. Induced emf and the number of turns of the coil (E vs. N)
   They are directly proportional. If you increase the number of turns of wire in the coil – by increasing the amount of individual conductors cutting through the magnetic field, the amount of induced emf produced will be the sum of all the individual loops of the coil.
2. Induced emf and magnetic flux (E vs. ɸ)
   Also directly proportional to one another. Increasing the magnetic flux means increasing the induced emf.
3. Induced emf and time (E vs. t)
   Inversely proportional. Increasing the time elapsed means decreasing the induction of emf.
4. Negative (-N)
   The reason behind that is that the negative sign means that the induced emf sends current in a direction so as to oppose the change in flux causing it.

For a special case of a conductor of length L moving perpendicular to a magnetic field B with a velocity, the induced emf called motional emf can be computed by:

RIGHT-HAND RULE 👍

The essence of the right hand rule and that is to determine the direction of the magnetic field produced by a current. The thumb tells the direction of the current, the four fingers determine the direction of magnetic field and the palm is for the direction of the force.

 

Electromagnetism Applications 🙂

Generators

A generator converts mechanical energy to electrical energy. It is usually utilized during power shutdowns and the like. While a motor is a generator working in reverse. It converts electrical energy to mechanical energy. And a transformer which is used to raise or lower the voltage of an AC source.

How I Learned 💖

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Honestly this is very hard. I’ve been challenged to this lesson and I am quite surprised to the result. The following are my ways to learn electromagnetism:

Advance Reading

I’ve done advance reading in this lesson in order for me to more understand the lesson. But even I’ve read a lot about this topic it was hard,

Activity

 

Our teacher gave us an activity. Where we should come up with the relationship of the variables to the equation given by Faraday and Lenz. Where I’ve realized that you should believe on what you know and what they knew. We tried our best to tell their relationships but our best is not that enough.

Reflection 👀

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Honestly, I swear, this is not that easy. Especially when we conducted the activity. But I’ve realized that electromagnetism is really important to us. To this generation we can’t live without electricity, we can’t do anything without it (somehow there are minimal amount), our life in earth must be so boring. In this lesson, you must believe to understand its concept.

But even how hard it is, it was worth it in the end. I really love how physics explains everything. Well, somehow, I’m a little bit proud of myself. More physics lessons for me! YEY!😎

Bibliography 🤞

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• Khan Academy. What is Faraday’s law? Retrieved at https://www.khanacademy.org/science/physics/magnetic-forces-and-magnetic-fields/magnetic-flux-faradays-law/a/what-is-faradays-law?fbclid=IwAR09TN-csb_nAUY0cMdNtlRtWtbkFNJTbDh-FdtYHQsZV5T9cRPAx7bo6mU
• Electromagnetic Induction video by It’s Aumsum Time. Published on May 8, 2015. Retrieved at https://www.youtube.com/watch?v=yA8gZM3fghc&feature=youtu.be&fbclid=IwAR0L3NEXArplnHhn2lItwT5rLgbgUokioMaW6U4DlExLxFOOS9NMrg1ogpE
• Using the right hand rule. Retrieved at https://www.khanacademy.org/test-prep/mcat/physical-processes/magnetism-mcat/a/using-the-right-hand-rule
• Definition of Magnetism. Retrieved at https://en.wikipedia.org/wiki/Magnetism
• The Magnetic Field. Retrieved at https://en.wikipedia.org/wiki/Magnetic_field

FIT IT UP!

Yipieeee! What’s up? Well, this is going to be my third blog for the second semester. And the lesson for today is about Capacitors! Yeyy! 👏👏 Now, scroll down and see the ideas I knew before the discussions, the lessons I learned from the discussions and activities, how I obtained these learning and lastly, my realizations after the discussions. Enjoy! 😁

Preliminary Knowledge 👶

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Honestly, I don’t remember any lessons about capacitors. But, according to my father, This would be a chicken nuggets for me. i hope he is right tho.

What I Learned… 👩‍🏫

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For us to understand easier the lesson about capacitors, we must first need to understand the basics:

What is Capacitor? 🤔

Capacitors are simple passive device that can store an electrical charge on their plates when connected to a voltage source

The capacitor is a component which has the ability or “capacity” to store energy in the form of an electrical charge producing a potential difference (Static Voltage) across its plates, much like a small rechargeable battery.

Different types of capacitors 😁

There are many different kinds of capacitors available from very small capacitor beads used in resonance circuits to large power factor correction capacitors, but they all do the same thing, they store charge.

• Ceramic capacitor:   The ceramic capacitor is a type of capacitor that is used in many applications from audio to RF. Values range from a few picofarads to around 0.1 microfarads. Ceramic capacitor types are by far the most commonly used type of capacitor being cheap and reliable and their loss factor is particularly low although this is dependent on the exact dielectric in use. In view of their constructional properties, these capacitors are widely used both in leaded and surface mount formats.
• Electrolytic capacitor:   Electrolytic capacitors are a type of capacitor that is polarised. They are able to offer high capacitance values – typically above 1μF, and are most widely used for low frequency applications – power supplies, decoupling and audio coupling applications as they have a frequency limit if around 100 kHz.
• Tantalum capacitor:   Like electrolytic capacitors, tantalum capacitors are also polarised and offer a very high capacitance level for their volume. However this type of capacitor is very intolerant of being reverse biased, often exploding when placed under stress. This type of capacitor must also not be subject to high ripple currents or voltages above their working voltage. They are available in both leaded and surface mount formats.

• Silver Mica Capacitor:   Silver mica capacitors are not as widely used these days, but they still offer very high levels of stability, low loss and accuracy where space is not an issue. They are primarily used for RF applications and and they are limited to maximum values of 1000 pF or so. 
• Polystyrene Film Capacitor:   Polystyrene capacitors are a relatively cheap form of capacitor but offer a close tolerance capacitor where needed. They are tubular in shape resulting from the fact that the plate / dielectric sandwich is rolled together, but this adds inductance limiting their frequency response to a few hundred kHz. They are generally only available as leaded electronics components.
• Polyester Film Capacitor:   Polyester film capacitors are used where cost is a consideration as they do not offer a high tolerance. Many polyester film capacitors have a tolerance of 5% or 10%, which is adequate for many applications. They are generally only available as leaded electronics components.
  

  The amount of charges stored in a capacitor per unit of electric potential is referred to as capacitance.

  Mathematically, it is computed using the following equation:

C is the capacitance of the capacitor,
Q is the magnitude of the charge stored on each plate, and
V is the voltage applied to each plate.
The unit used to measure capacitance is coulomb per volt (C/V) or Farad (F).

A capacitors’ capacitance is dependent on various factors.

The battle summarizes these factors and their respective effects to the capacitance of a capacitor

Variable		Effect on Capacitance
Area of the conducting plate	Increase	Increase
	Decrease	Decrease
Distance between the conducting plates	Increase	Increase
	Decrease	Decrease
Type of dielectric	More conducting	Decrease
	Less conducting	Increase

This implies that storing greater amount of charges in the capacitor results in greater energy stored inside it.

• Capacitors function when they are connected to a circuit. Separate treatments should be done for capacitors connected in series and in parallel.

Series Connection ❤

A series circuit can be constructed by connecting light bulbs in such a manner that there is a single pathway for charge flow; the bulbs are added to the same line with no branching point. As more and more light bulbs are added, the brightness of each bulb gradually decreases. This observation is an indicator that the current within the circuit is decreasing.

So for series circuits, as more resistors are added the overall current within the circuit decreases. This decrease in current is consistent with the conclusion that the overall resistance increases.

The formula here shows that the total charge stored by the circuit containing the capacitors is of equal amount or constant throughout.

q total= q1 = q2 = q3 = …= qn

Meanwhile, this formula shows that the total voltage in the circuit containing the capacitors varies on the amount of voltage across each capacitor. The total voltage is equal to the sum of the individual voltages of the capacitors in the circuit.

V total= V1 + V2 + V3 + … + Vn

The third formula shows that the reciprocal of the total capacitance due to the capacitors in the circuit is equal to the sum of the individual reciprocals of each capacitance. This means that capacitors connected in series provide a low capacitance. Note that the total capacitance is lower than the individual capacitances of the capacitors in a series circuit.

1/C total = 1/C1 + 1/C2 + 1/C3 + … 1/Cn

Parallel Connections 💕

Using the same collection of wires, D-cells and bulbs, parallel circuits can be explored in the same manner. The effect of the number of resistors upon the overall current and the overall resistance can be investigated. The diagram below depicts the usual means of constructing the circuit with parallel connections of light bulbs.

It is clear from observing the indicator bulbs in the above diagrams that the addition of more resistors causes the indicator bulb to get brighter. For parallel circuits, as the number of resistors increases, the overall current also increases. This increase in current is consistent with a decrease in overall resistance. Adding more resistors in a separate branch has the unexpected result of decreasing the overall resistance!

The formula here shows that the total charge in the circuit containing the capacitors varies on the amount of charge stored in each capacitor. The total charge is equal to the sum of the individual charges stored in the capacitor in the circuit.

q total = q1 =q2 = q3 = … qn

The second formula here shows that the total voltage stored by the circuit containing the capacitors is equal amount or constant throughout.

V total = V1 = V2 = V3 = … Vn

Finally, the third formula here shows that the total capacitance in the circuit containing the capacitors varies on the capacitance of each capacitor. The total capacitance is equal to the sum of the individual capacitance stored in the capacitors in the circuit.

C total = C1 + C2 + C3 +… Cn

How I Learned 💖

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Capacitors was a bit tricky but with the help of the following I was able to learn it!

Advance Reading

Just like the previous lesson I’ve done advance reading in this lesson in order for me to more understand the lesson.

Discussions

With the help of our professor I’ve understand easier this lesson.

Problem Solving Practice

I am doing trial-and-error thingy every night for me to master the problem-solving lessons in physics.

Reflection 👀

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Honestly, I swear, this is not that easy. It wasn’t a chicken nuggets for me. I don’t know why but this is quiet challenging for me. Of course, I can’t remember anything about this lesson, maybe I am absent when they tackle this in my JHS.

But even how hard it is, it was worth it in the end. I really love how physics explains everything. Well, somehow, I’m a little bit proud of myself. More physics lessons for me! YEY!😎

Bibliography 🤞

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https://www.physicsclassroom.com/class/circuits/Lesson-4/Two-Types-of-Connections 

https://www.physicsclassroom.com/class/circuits/Lesson-4/Combination-Circuits

🙂Ohm 😎Coulomb

Hello readers!! Welcome back! This is going to be my second blog for the second or last semester. And the lesson for today is about the Coulomb’s Law! Now, scroll down and see the ideas I knew before the discussions, the lessons I learned from the discussions and activities, how I obtained these learning and lastly, my realizations after the discussions. Enjoy! 😁

Preliminary Knowledge 👶

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With the help of the previous lesson, I thought Coulomb’s Law would be easy. And I also think Coulomb’s Law is just like Newton’s Law, I hope so. And I also believe that Gravitational force is stronger than the Electric force.

What I Learned… 👩‍🏫

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For us to understand easier the coulomb’s law, we must first need to understand the following:

Electrons are the essence of electricity

Electric Fields 🤷‍♂️

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Key Takeaways:

• An electric charge is a property of matter that causes two objects to attract or repel depending on their charges (positive or negative).
• An electric field is a region of space around an electrically charged particle or object in which an electric charge would feel force.
• An electric field is a vector quantity and can be visualized as arrows going toward or away from charges. The lines are defined as pointing radially outward, away from a positive charge, or radially inward, toward a negative charge.

This phenomenon is the result of a property of matter called electric charge. Electric charges produce electric fields: regions of space around electrically charged particles or objects in which other electrically charged particles or objects would feel force.

Gravitational Field vs Electric Field 👊

To answer this question divide it into two parts: Similarities and Differences.  Similarities 💕

 Both gravitational and electric forces acting in the fields are inversely proportional to the square root of distance/radius. They both act between two bodies without contact. Both gravitational and electric fields have field strength that also follows this inverse square law in relation to distance.  Mass/charge in a gravitational field/electric field has potential.

Differences 💔

Gravitational force is always attractive while electric force can be both attractive and repulsive. Electric force is much stronger than gravitational force. Gravitational force acts on mass while electric force acts on charge.

 

It is useful to also draw diagrams to demonstrate gravitational and electric fields to support your answer.

Diagram Example

The gravitational force arises from a gravitational field while electric force arises from a electric fields.

TRIVIA101 😮

1. Did you know that the electric force keeps you from falling to the center of the earth? It is because the electric force is much stronger than the gravitational force.
2. A tiny magnet beats the gravity of the whole planet
3. Any charge object creates an electric fields

Electric field lines 🤗

Remember that the lines are directed away from positively charged source charges,

while toward negatively charged source charges.

And now we are proceeding to our main topic the Coulomb’s Law… ✨

Charles-Augustin de Coulomb 🧑

 

He is a farench physicist best known for the formulation of Coulomb’s law, which states that the force between two electrical charges is proportional to the product of the charges and inversely proportional to the square of the distance between them. Coulombic force is one of the principal forces involved in atomic reactions.

 

Coulomb’s Law very nicely describes this natural phenomenon. The law has this form,

Identical to Newton’s Law of Universal Gravitation

Coulomb’s Law Vs Newton’s Law of Universal Gravitation ⚡

Coulomb’s Law describes the electric force between two charges and is:

Newton’s Law of Gravitation describes the gravitational force between two masses and is:

Both equations have a constant (k or G) and both include the product of two variables. In Coulomb’s Law, q1 and q2 are charges and in Newton’s Law of Gravitation m1 and m2 are masses. The dominant factor for both equations is the inverse square of the distance between either the two charges or the two masses. The variable r is the distance between two charges or two masses. The Coulomb’s constant is equal to 8.99×10⁹ N·m²/C² while the Newton’s constant is 6.67 x 10 ^-11 Nm² /kg ^-2

REMINDERS ✔

• Electric force Increases as charge (q) Increases
• Electric Force Decreases as distance (d) Increases
• (More than two Charges Require Vector analysis)

Ready for the problem-solving? 😉

Sample Problem 1 💕

Superposition Principle 📖

This principle states that…

The total electric force a particular charge experiences due to a number of other charges is the vector sum of all individual forces

Which means, each of these charges will exert a force on the charge as if no other charges.

Sample Problem 2 💖

Sample problem 3 ❤

Sample problem 4 😍

How I Learned 💖

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Coulomb’s Law was a bit tricky but with the help of the following I was able to learn it!

Advance Reading

Just like the previous lesson I’ve done advance reading in this lesson in order for me to more understand the lesson.

Tutorial Videos

I’ve watched videos in Youtube for me to understand hard topics. Including computations.

Discussions

With the help of our professor I’ve understand easier this lesson.

Problem Solving Practice

I am doing trial-and-error thingy every night for me to master the problem-solving lessons in physics.

Reflection 👀

---

Annnnnd another lessons are gained and another self-realizations has been made! I’ve learned to much about the Coulomb’s Law in this lesson.

I’ve realized that Coulomb’s Law is not like the Newton’s Law, and also Electric force is much stronger than the Gravitational force. A lot. And it is needed to get your calculator every time.

Well thank you for reading this blog, hope you learn something. Thank you!

Bibliography 🤞

---

Electric Force. Retrieved from…

https://www.khanacademy.org/science/electrical-engineering/ee-electrostatics/ee-electric-force-and-electric-field/a/ee-electric-force

Electric Field. Retrieved from…

https://en.wikipedia.org/wiki/Electric_field

Gravitational Field vs Electric Field. Retrieved from…

https://www.mytutor.co.uk/answers/17058/A-Level/Physics/Compare-gravitational-and-electric-fields/

Electric Field Lines. Retrieved from…

https://www.physicsclassroom.com/class/estatics/Lesson-4/Electric-Field-Lines

Charles-Augustin de Coulomb. Retrieved from…

https://www.britannica.com/biography/Charles-Augustin-de-Coulomb

Coulomb’s Law Vs Newton’s Law of Universal Gravitation. Retrieved from…

https://study.com/academy/answer/how-is-coulomb-s-law-similar-to-newton-s-law-of-gravitation.html

“AMBER waiting for you” 😍

Hello! This is my first blog for the second or last semester. This mainly revolves with electroscope. Now, scroll down and see the ideas I knew before the discussions, the lessons I learned from the discussions and activities, how I obtained these learning and lastly, my realizations after the discussions.

Preliminary Knowledge 👶

---

In Chemistry, we already talked about the atom and its sub-atomic particles, so I am familiar with it and I do believe that atom is the smallest particle of matter or I’m wrong. Also the famous quote, “Unlike charges attracts and like charges repel” was discussed to us. But further lessons about electricity and electroscope is not involved.

What I Learned… 👩‍🏫

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Before we proceed to our main topic, let us first learn the basics.. ❤

What is electricity? 🤔

• Well, electricity is a property of matter that results from the presence or movement of electric charge.
• And also, electricity is responsible for many well-known physical phenomena such as lightning, electric fields and electric currents, and is put to use in industrial applications such as electronics and electric power.

  If it weren’t for electricity, we’d all be watching television by candlelight.

The Origin of Electricity 😮

Amber is fossilized tree resin, which has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects. Amber is used in jewelry. It has also been used as a healing agent in folk medicine.

Electricity comes from the Greek word “elektron” which means amber.

Early History of Electricity 🧓

The history of electricity started with William Gilbert, a physician who served Queen Elizabeth the first of England. Before William Gilbert, all knowledge about electricity and magnetism was that the lodestone has magnetic properties and that rubbing amber and jet would draw bits of stuff to create sticking. Motivated and learned by William Gilbert several Europeans inventors, Otto von Guericke of Germany, Charles Francois Du Fay of France, and Stephen Gray of England, extended the knowledge. Otto von Guericke though his research proved that a vacuum could exist.

Electric Charge ⚡

Benjamin Franklin (1706-1790)

A giant leap of understanding was required to explain observations like these in terms of positive and negative electrical charge. In the 18th century, Benjamin Franklin in America tried experiments with charges. It was Franklin who named the two kinds of electricity ‘positive’ and ‘negative’. He even collected electric charges from thunderstorm clouds through wet string from a kite. 

 

“If you feel empty, how about an atom?”

Atom 📖

Atoms are the basic units of matter and the defining structure of elements. The term “atom” comes from the Greek word for indivisible, because it was once thought that atoms were the smallest things in the universe and could not be divided. We now know that atoms are made up of three particles: protons, neutrons and electrons — which are composed of even smaller particles such as quarks.

The Subatomic particles

“Opposite charges attracts, and like charges repel”

Atomic Structure 👌

Well, the following are the different structure of an atom proposed by five great scientist:

JJ Thomsons

Rutherford

Bohr

Schrodinger

The Triboelectric Series 💕

But first, what does triboelectric series mean? It is a sequence of substances so arranged that any one of them is positively electrified by rubbing it with any other substance farther on in the list. Lets proceed!

Now we know the basics, lets go to our main topic the…

Electroscope 🤗

An electroscope has a metal detector knob on top which is connected to a pair of metal leaves hanging from the bottom of the connecting rod.

Note when no charge is present the metal leaves hang loosely downward. However, if an object with a charge is brought near the electroscope, one or two thins can happen. 

If the charge is positive, electrons in the metal of the electroscope are attracted to the charge and move upward out of the leaves. This causes the leaves to have a temporary positive charge and because like charges repel, the leaves separate. When the charge is removed, the electrons return to their original positions and leaves relax.

Likewise, if the charge is negative, the electrons in the metal of the electroscope are repelled and move toward the leaves. This causes the leaves to have a temporary positive charge and because like charges repel, the leaves again separate. Then when the charge removed, the electrons return to their original position and leaves relax.

So, an electroscope reacts to the presence of a charge through the movement of electrons either into, or away from, the leaves. In either case, the leaves separate.

Electric Dipoles 🤞

 

^{Theoretically, an electric dipole is defined by the first-order term of the multipole expansion; it consists of two equal and opposite charges that are infinitely close together. This is unrealistic, as real dipoles have separated charge. However, because the charge separation is very small compared to everyday lengths, the error introduced by treating real dipoles like they are theoretically perfect is usually negligible. The dipole’s direction usually points from the negative charge towards the positive} charge.

 

How I Learned 💖

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These topics are not easy to understand but I wouldn’t be able to share with you these learnings if not because of these ways which helped me a lot to understand the topics:

Advance Reading

 

I’m doing advance reading in every lesson in physics for me to more understand the lesson.

Tutorial Videos  

I watch videos in Youtube for me to understand hard topics. Including computations. 

Discussions

 

Well, with the help of our teacher in physics, I am able to understand these lessons. Thanks to him.

 

Group Activity

 

Doing group activity is such a big help for me. I can share my knowledge to them and so to them. I was not only enjoying, but also learning with them.

Reflection 👀

---

Nothings exists except atoms and empty space; everything else is opinion.

Another lessons are gained and another self-realizations has been made. I’ve learned to much about electricity in this lesson.

I’ve realized that it is not the atom, but the amber. The amber is the smallest particle of matter. For all those times. I am today’s year old that I knew this thing. What a misconception.

And also atom is much more empty than any other things. So if you feel empty, how about an atom? Imagine a soccer field, and a one piece of grain is its mass. Feel empty?haha. This made my day.

Well thank you for reading this blog, hope you learn something. Thank you! 

Bibliography

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The Origin of Electricity | EEWeb Community 

https://www.eeweb.com/profile/andrew-carter/articles/the-origin-of-electricity

The Structure of the Atom | Boundless Chemistry – Lumen Learning

https://courses.lumenlearning.com/boundless-chemistry/…/the-structure-of-the-atom/

 

Materials that Cause Static Electricity by Ron Kurtus – Physics Lessons …

https://www.school-for-champions.com/science/static_materials.htm

What is the principle of an electroscope | eNotes

https://www.enotes.com/homework-help/what-principle-an-electroscope-252973

 

Electric dipole moment – Wikipedia

https://en.wikipedia.org/wiki/Electric_dipole_moment

 

 

Say HI!

In this blog, we’re going to learn about waves.

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Oscillations or vibration

A wiggle in time

Example:

Periodic motion of a pendulum where the bob swings back and forth

Waves

A wiggle in both space and time

Example:

Water waves, sound waves, waves on the string and electromagnetic wave.

Note that wave is the disturbance and transfer of energy but not transfer of matter

Equilibrium point

The initial position of the bob when it is at rest and in equilibrium

Equilibrium line

The initial length of the string

Properties of Waves

1. Able to reflect
2. Able to bend

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Mechanical wave

A kind of wave that requires a medium to propagate

Example:
Sound wave
is a pressure disturbance that travels through a medium by means of particle-to-particle interaction

Types of Mechanical Waves

1. Transverse wave
The direction of the motion of particles is perpendicular to the direction of the propagation of the wave.

Parts of transverse wave:

• Equilibrium line– the stable position of the medium when it is in equilibrium
• Crest– the highest point in a transverse wave

• Trough– the lowest point in a transverse wave
• Amplitude– the distance from the equilibrium line to the crest or trough

2. Longitudinal wave
The direction of the motion of the particles and the direction of the motion of the particles and the direction of the propagation of the waves are in the same line.

Parts of Longitudinal wave:

• Compression- the region of high practice density.

• Expansion or Rarefaction- the low region of low particle density.

3. Both Transverse and Longitudinal wave
Also called as Rayleigh surface wave.
Example: the ripples of waves on the surface of water.

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Periodic Motion

• The oscillation of an object around a point
• Refers to motion that repeats itself regularly or at equal time intervals

Frequency (f)

The number of complete revolutions or cycles of the ball around the circle per unit of time.

Simple Harmonic motion (SHM)

“A body is moving in simple harmonic motion if its acceleration is proportional and oppositely directed to its position”

Interference

A wave comes together (superpose) with another wave

Standing wave

If one end of the string is continuously moved up and down, the incident wave will interfere with the reflected wave that result in an interference pattern.

Nodes

The points in a wave where the particles are relatively at rest.

Antinodes

The positions of maximum transverse displacement.

Comparison of Transverse and Standing wave

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Fundamental Frequency and Harmonics

A string with L is held at both ends in rigid supports. The first four standing waves called the normal modes or resonant frequencies of the string are shown in the figure. Find the frequency of these normal modes.

Fundamental frequency or first harmonic

The first normal mode with only one anitode

Second harmonic or first overtone

The second normal mode has two antinodes

Third harmonic or second overtone

The third mode

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Sound

Sound wave

• The longitudinal wave that is very important in ou daily life
• Is a pressure disturbance that travels through a medium by means of particle-to-particle interaction

Like any wave, the speed of a sound wave refers to how fast the disturbance is passed from particle to particle.

speed = distance/time

The faster a sound wave travels, the more distance it will cover in the same period of time.

Factors Affecting Wave Speed

• Human Error
• Barriers (noise)
• Temperature

The Wave Equation Revisited

The mathematical relationship between speed, frequency and wavelength is given by the following equation.

Speed = Wavelength • Frequency

Using the symbols v, λ, and f, the equation can be rewritten as

v = f • λ

Example:
An automatic focus camera is able to focus on objects by use of an ultrasonic sound wave. The camera sends out sound waves that reflect off distant objects and return to the camera. A sensor detects the time it takes for the waves to return and then determines the distance an object is from the camera. If a sound wave (speed = 340 m/s) returns to the camera 0.150 seconds after leaving the camera, how far away is the object?

Answer = 25.5 m
The speed of the sound wave is 340 m/s. The distance can be found using d = v • t resulting in an answer of 25.5 m. Use 0.075 seconds for the time since 0.150 seconds refers to the round-trip distance.

---

Doppler effect

The frequency of sound heard by the listener changes because of the relative motion between the source of sound and the listener

---

Thanks for reading, hope you learn something.

Please note that the information above is taken from a “General Physics 1” book. Published and exclusively distributed by DIWA LEARNING SYSTEMS INC.

SANSINUKOB

What I know

---

I love the universe. But I don’t have the enough knowledge about it, and I don’t have background knowledge in this lesson but I have atleast little knowledge in the lesson “Torque.” So, I’ve been doing advanced reading to this topic to become active in class discussions and I am amazed that I can go with the flow.

What I learned

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In this lesson, I’ve learned so many things. Here are the following:

Torque

(due to a force) causes angular acceleration

Torque=(force)x(moment arm)
τ=±Fl

Moment arm is the perpendicular distance between the axis of rotation and the point where the force is applied.

Torque=(perpendicular force)x(distance)
τ=±F d

Picture 1. Torque can also define as τ=rxF

Picture 2. EXAMPLE PROBLEM

Picture 3. EXAMPLE SOLUTION

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Kepler’s Three Laws

Picture 4. Kepler

Picture 5. Johannes Kepler short biography

First law (The Law of Ellipse)

The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus.

Picture 6. An elliptical orbit of a Planet

Second Law (The Law of Equal Areas)

The speed at which any planet moves trough space is constantly changing
Casual area over change of time

Picture 7. Second Law

Third Law (The Law of Harmonies)

Makes comparison between the motion characteristics if different planets. It is the ratio of the squares of the periods to the cubes of their average distances from the sun is the same for every one of the planets.

Picture 8. An illustration that consider the orbital period and average distance from the sun (orbital radius) for Earth and Mars as given.

Picture 9. Amazingly, every planet has the same T2/R3 ratio.

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Newton’s Law of Universal Gravitation

Picture 10. Isaac Newton

 

Picture 11. Isaac Newton short biography

 

The Universal Gravitation Equation

(About the universality of gravity)
All objects attract each other with a force of gravitational attraction.

Picture 12. Formula

 

Picture 13. Newton’s Gravitation Equation

Picture 14.

Problem
Determine the force of gravitational attraction between the earth (m=5.98×1024 kg) and a 70-kg physics student if the student is in an airplane at 40000 feet above earth’s surface. This would place the student a distance of 6.39×106 m from the earth’s center.

Picture 15. Solution

• Distance and Force of gravity has a inverse relationship.
• The use of Newton’s universal gravitation equation to calculate the force of gravity yields the same result as when calculating using this formula Fgrav=m*g

  

  Picture 16. Solution

How I learned

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1.Advance Reading

Picture 17. Reading is very helpful. Really helpful. This helps me a lot. Seriously.

2. Little Teacher

Picture 18. I don’t have any photo of the little teacher but this would be a proof. This is a photo of the activity given by the reporters (Jerrimae and Jomarie)

3. Video Tutorials

 

Picture 19. The video/s I watched to more understand the lesson.

4. Activity

Picture 20. The activity given to understand the Kepler’s Three Laws

Reflection

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The Universe is wide as we can imagine. Yet, our mind keeps on seeking knowledge until we unluck the curiousity in our eyes.

In this lesson, it was extra ordinary. Why? Because I am really amazed about the place we live. Yes we still lack in what we are. But we’re doing everything to have what we need not what we want.

Physics? Yes, a very hard branch of science. Understanding the lesson was not easy. Suit yourself for another adventurous journey in physics.

Bibliography

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• Newton’s Law of Universal Gravitation. The Physics Classroom. Retrieved from https://www.physicsclassroom.com/Concept-Builders/Circular-and-Satellite-Motion/Universal-Gravitation
• Kepler’s Three Laws. The Physics Classroom. Retrieved from https://www.physicsclassroom.com/class/circles/Lesson-4/Kepler-s-Three-Laws
• Torque. The Physics Classroom. Retrieved from https://www.physicsclassroom.com/class/Torque

Momento de Inercia y Movimiento Rotacional

What I Know

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Inertia is not new to me because of the Newton’s Law that was discussed already in the first grading. And I’ve been doing advanced reading to this topic to become active in class discussions. This was expectation vs. reality, I thought it was going to be hard but no, it was really fun.

What I Learned

---

In Moment of Inertia and Rotational Motion, there are much important and interesting lessons I have learned and here are as follows:

Moment of Inertia Defined

• The rotational inertia of a solid object about an axis is greater when more of its mass is further from the axis.
• Imagine breaking an object up into small pieces of mass (Δm) at different (r) from the axis. The moment of inertia is the sum over pieces of Δmr2

I = ΣΔmr2

• Because tangential acceleration of a point in a rigid object is proportional to distance from the axis, and because torque is also proportional to moment arm, the contribution to rotational inertia of each mass point in a rigid object is proportional to the square of its distance from the axis. That’s the reason Moment of inertia is defined this way.

Picture 1. Example Problem in finding the Moment of Inertia

Rolling Down an Incline

Picture 2. Solid cylinder and hollow cylinder rolling down an incline

• To roll down an incline, a round object must accelerate both rotationally and translationally.
• The rolling object with the biggest rotational inertia has the smallest acceleration.
• Note that it is the friction is necessary to give the rolling object rotational acceleration that slows down its translational acceleration.

Moments of Inertia

Picture 3 and 4. These formulas are for the moments of inertia of rigid objects with simple geometric shapes are obtained by applying the definition of moment of inertia.

Radius of Gyration (k)

• Distance from any given axis which the mass of a body may be assumed concentrated without altering the moment of inertia of the body

Picture 5. Radius of Gyration Formula

where I=rotational motion and m=mass

Picture 6. Example Problem in finding the Radius of Gyration

Parallel Axes Theorem

• Moment of inertia (I) of a body about any axis that is parallel to an axis passing through its center of mass is equal to the moment of inertia (Ic) plus the product of its mass (m).

I=Ic+md2

Picture 7. Example problem in finding momemt of inertia at the edge

Dynamics of Rotation (Newton’s Law of Rotation)

• Second Law: Unbalanced torque acting on a rigid body produces angular acceleration. This angular acceleration is directly proportional too and in the same direction sense as the unbalanced torque and inversely proportional to the body’s moment of inertia about the axis of rotation.

τ=Iα

Net torque

• Causes a system to have an angular acceleration. The proportionality constant is the moment of inertia.

Στ=Iα

• The moment of inertia (I) depends on the system’s mass and how it is distributed.

Rotational Motion

• If the net torque is zero, then Iꞷ is constant

Angular Momentum Defined

Picture 8. Definition of Angular Momentum

Conservation of Angular Momentum Principle:

• If the total external torque on an object is zero, then the total angular momentum of the object is constant (conserved)

Picture 9. Examples of Conservation of Angular

Rotational Analogs

Picture 10. Rotational Analogs

1.Angular Velocity

• Angular Velocity is a measure of how quickly an object moves through an angle. It is the change in angle of a moving object (measured in radians), divided by time. Angular velocity has a magnitude (a value) and a direction.

Angular velocity = (final angle) – (initial angle) / time = change in position/time

ω = (θ_f – θ_i) / t

ω = angular velocity

θ_f = the final angle

θ_i = the initial angle

t = time

Δθ = short form for ‘the change in angle’

Example : The second hand of a clock takes 30 seconds to move through an arc of 180 degrees. What is the angular velocity?
Answer: The second hand starts at θ_i = 0 degrees and moves to θ_f = 180 degrees from the point of origin. 180 degrees = 1/2 of a full revolution, so θ_f = (0.5 x 2 π). (360 degrees is 2π rad). The time it takes for the second hand to move through 180 degrees is 30 seconds, so t = 30 s. We can now calculate the angular velocity.

ω = (θ_f – θ_i) / t

ω = (0.5 x 2π ) rad / 30 s

ω = (π) rad / 30 s = 3.14 rad / 30 s

ω = 0.105 rad/s

2. Angular Acceleration

Angular acceleration α is defined as the rate of change of angular velocity. In equation form, angular acceleration is expressed as follows:

Picture. Formula for Angular Acceleration

where Δω is the change in angular velocity and Δt is the change in time. The units of angular acceleration are (rad/s)/s, or rad/s². If ωincreases, then α is positive. If ω decreases, then α is negative.

3.Angular Speed

Angular speed is the rate at which an object changes its angle (measured) in radians, in a given time period. Angular speed has a magnitude (a value) only.

Angular speed = (final angle) – (initial angle) / time = change in position/time

ω = θ /t

ω = angular speed in radians/sec

θ = angle in radians (2π radians = 360 degrees)

t = time, sec

Angular speed and angular velocity use the same formula; the difference between the two is that Angular speed is a scalar quantity, while angular velocity is a vector quantity.

Example: The earth rotates once on its axis every 24 hours. What is its angular speed?
Answer: The angle traversed, 1 rotation, means that θ = 2π. The time for this rotation, t = 24 hr. Time must be converted to seconds.

t = 24 hr x 60 min/hr x 60 sec/min = 86400 sec

ω = θ /t

ω = 2π/86400 sec

ω = 0.0000726 radians/sec = 7.26 x 10-5 rad/sec

Torque

• (due to a force) causes angular acceleration

Torque=(force)x(moment arm)

τ=±Fl

• Moment arm is the perpendicular distance between the axis of rotation and the point where the force is applied.

Torque=(perpendicular force)x(distance)

Picture 11. Formula for Torque

• Torque can also define as τ=rxF

EXAMPLE PROBLEM

Picture 12. Example Problem for the Rotational Motion

How I Learned

---

I’ve tried different techniques in order to learn faster and it doesn’t failed me, I’ve always learn new things. It is very challenging yet helpful and it urged me to learn and discover more. Here are the following:

Advance Reading

In order for me to understand this lesson better. I need to read and read and read. But don’t forget to analyze. Well it was fulfilling if I can go with the flow in class discussions.

Video Tutorials

The videos I’ve watched is very helpful for me. Especially in computation and solving problems. It helps me open up my mind.

Activities or Experiments

This is very helpful in order for us to believe that Physics is true. That every computations we makes can apply in real life situations.

Reflection

---

We must nevertheless present all possible interpretations for each observation, so that competing theories can be formulated and defended. In science, as elsewhere, intellectual inertia, the fashions of the moment, the weight of institutions, and authoritarianism are always to be feared. Heresies play an essential role by keeping our minds argumentative and alert. — Hubert Reeves

In this lesson, I’ve learned so many things about the Moment of Inertia and Rotational Motion. Especially in finding the moment of inertia at the center or at the edge. And also finding the torque of an object.

It was really fun to study if you can understand physics. You know the feeling of not having torns in your heart when reading this chapter. It was really good.

And now, I think I’m ready for the next battle.

Bibliography

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• Hollow cylinder vs solid cylinder. Physics Stack Exchange. Retrieved from https://physics.stack.exchange.com/questions/276697/hollow-cylinder-vs-solid-cylinder
• Inertia and Mass. Physics Classroom. Retrieved from https://www.physics.classroom.com/class/newtlaws/Lesson-1/Inertia-and-Mass
• Dynamics of Rotational Motion: Rotational Inertia. Retrieved from https://cnx.org/contents/21n2Vucl@6/Dynamics-of-Rotational-Motion-Rotational-Inertia
• Physics: Torque. Slide Player. https://slideplayer.com/slide/4428187/
• Rotational Dynamics. Physics 201. Retrieved from https://physics.bgsu.edu/stoner/p201/rotdyn/sld0001
• Angular Velocity Formula. Retrieved at http://www.softschools.com/formulas/physics/angular_velocity_formula/21/
• Angular acceleration. Retrieved at https://courses.lumenlearning.com/physics/chapter/10-1-angular-acceleration/
• Angular speed. Retrieved at http://www.softschools.com/formulas/physics/angular_speed_formula/27/

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Movimiento De Proyectiles

WHAT I KNOW

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Before, I just believed in the concept that the only force acting upon an upward moving projectile is just gravity.  That’s why it falls down because of the power of gravity only. However, this idea changed after the discussion and activities of this lesson.

WHAT I LEARNED

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Projectile

– is an object upon which the only force acting is gravity.

-is any object that once projected or dropped continues in motion by its own inertia and is influenced only by the downward force of gravity.

Examples of projectiles

• An object dropped from rest is a projectile (provided that the influence of air resistance is negligible);
• An object that is thrown vertically upward is also a projectile (provided that the influence of air resistance is negligible); and
• An object which is thrown upward at an angle to the horizontal is also a projectile (provided that the influence of air resistance is negligible).

Facts on Projectile

1. The motions along perpendicular axes are independent and thus can be analyzed separately, where vertical and horizontal motions were seen to be independent.
2. Velocity  is tangent to the path. The velocity of the vector changes as the path curves downward. The actual velocity of the projectile is directed tangent to its trajectory.
3. The horizontal velocity is constant, the vertical velocity decreases because of the pull of gravity at the top of its path, the vertical component of the velocity is zero. The velocity then is purely horizontal.

Two important things to emphasize

• First, anywhere along its path of the projectile, its acceleration is the constant acceleration due to gravity “g” , which has magnitude 9.8m/s² and is directed downward.
• Second, at the top of its path only the vertical velocity is zero. At this point, the velocity is purely horizontal because the horizontal velocity is held constant.

Projectile Practice Problem

This is an example problem of projectile motion given in the video presentation.

HOW I LEARNED

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In order to understand Projectile motion the combination of video presentations and activities helped me. Here are the following:

1. Catapult Making

The photo below is the catapult we made. Where we won, as doing the activity.

2. Catapult Activity

 

 

The photos were taken when we are doing the catapult activity. It was fun and I understand why the mallow reach its longest distance and highest peak, it is because of the angle of the catapult and its initial velocity which are the rubber bands.

3. Video Presentation

The list of videos for better understanding Projectile Motion

 

REFLECTION

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The things I learned in projectile motion is that objects that are thrown will get affected by factors of gravity, air resistance, and weight. I didn’t know that gravity doesn’t affect the horizontal distance.  Also the weight of the object can also change the distance and the way it travels. I have also learned how to use the equations to find the projectile motion. I have also learned that many factors affect the way objects moves, like angle and the initial velocity.

Before I end this blog, I want to left a quote made by a really good person in connection of projectile and life. Here it goes:

Life is like a projectile motion how much hard work you will do as maximum velocity then it will have maximum height as success -Vashal Kumar

 

Bibliography

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• PhysicsClassroom:Vectors – Motion and Forces in Two Dimensions – Lesson 2 – Projectile Motion. Retrieved from   http://www.physicsclassroom.com/class/vectors/Lesson-2/What-is-a-Projectile
• Lumen Physics:Projectile Motion. Retrieved from https://courses.lumenlearning.com/physics/chapter/3-4-projectile-motion/
• What is a Projectile? Retrieved from https://physicsabout.com/projectile-motion/