Parth G | Kinetic Energy EXPLAINED in 5 Levels - Beginner to Advanced (Classical Physics by Parth G) @ParthGChannel | Uploaded 2 years ago | Updated 7 minutes ago
What is kinetic energy? How does it depend on the mass and speed of an object? And how do relativity and quantum mechanics deal with it? We'll answer all of these questions in this video, in 5 levels of difficulty.
Level 1 - Kinetic energy is the energy that an object has when it is moving. The faster it moves, the more kinetic energy it has. Energy is a quantity or number that we can assign to different parts of whatever we are studying, in order to predict how it should behave at some point in the future (based on Conservation of Energy). Kinetic energy (just like other forms of energy) is measured in Joules.
Level 2 - The formula for kinetic energy is (1/2)mv^2 where m is the mass of our object, and v is its speed. So we find that if we double an object's speed, its kinetic energy increases fourfold. If we double the mass of the object, its kinetic energy increases twofold. It's worth noting that v refers to the speed of the object, not the velocity. In other words, kinetic energy is a scalar.
Level 3 - We've mentioned the speed of an object multiple times here... but what is this speed measured relative to? Whenever we measure the speed of an object, this means the object is moving a certain distance away from some reference point, in every unit of time. From different reference frames, an object may be moving at different speeds. Therefore, these different frames may decide the object has different amounts of kinetic energy. Which is correct? The answer is all of them! Reference frames do not need to agree on how much kinetic energy an object has. As long as the total energy in each frame is conserved, that's all that matters. So to one observer an object may have no kinetic energy, while to another the same object may have kinetic energy... and this is ok!
Level 4 - In special relativity, every object has a certain amount of energy, even when at rest relative to the observer. This energy is given by the famous equation E = mc^2. However when the object is moving, the energy-mass-momentum equivalence equation (a much more complicated one) takes effect. In this video we discuss one of the basic assumptions in special relativity, that the speed of light is constant for all observers. We then also see that the kinetic energy of an object in any reference frame, is the energy it has while moving, minus the energy it had when it was stationary. Upon using a binomial expansion for small velocities, we see that the main (biggest) term of the relativistic kinetic energy equation is the same as the classical, Newtonian kinetic energy equation! However in relativity there are infinitely many terms getting smaller and smaller.
Level 5 - We've only talked about linear kinetic energy so far. We can also consider the rotational kinetic energy of an object when it is undergoing some sort of angular motion. The rotational kinetic energy depends on the angular speed of our object, and on its moment of inertia. The angular speed is simply how much angle is covered by our object per unit time. And the moment of inertia is the equivalent of mass for angular motion. Just like mass is a measure of how hard it is to move an object in a straight line, the moment of inertia is a measure of how hard it is to move it in an angular manner. The moment of inertia depends on both the mass of the object, as well as its shape.
Resources to check out:
Kinetic Energy, Conservation of Energy Different Reference Frames: https://en.wikipedia.org/wiki/Kinetic_energy
Constant Speed of Light: https://en.wikipedia.org/wiki/Speed_of_light
Rotational Kinetic Energy: https://en.wikipedia.org/wiki/Rotational_energy
Moment of Inertia: https://en.wikipedia.org/wiki/Moment_of_inertia
Many of you have asked about the stuff I use to make my videos, so I'm posting some affiliate links here! I make a small commission if you make a purchase through these links.
A Quantum Physics Book I Enjoy: https://amzn.to/3sxLlgL
My Camera (Sony A6400): https://amzn.to/2SjZzWq
ND Filter: https://amzn.to/3qoGwHk
Microphone and Stand (Fifine): https://amzn.to/2OwyWvt
Gorillapod Tripod: https://amzn.to/3wQ0L2Q
Thanks so much for watching - please do check out my socials here:
Instagram - @parthvlogs
Patreon - patreon.com/parthg
Music Chanel - Parth G's Shenanigans
Merch - https://parth-gs-merch-stand.creator-spring.com/
Timestamps:
0:00 - Intro: Kinetic Energy by Parth G
0:31 - Level 1 - What is Kinetic Energy? How do we measure it?
1:37 - Level 2 - The Formula for Kinetic Energy EXPLAINED
3:54 - Level 3 - Kinetic Energy in different Reference Frames!
5:52 - Level 4 - How does Special Relativity deal with Kinetic Energy?
9:54 - Level 5 - Rotational Kinetic Energy, and Quantum Mechanics
12:17 - Thanks for Watching! Please Subscribe for more Fun Physics!
What is kinetic energy? How does it depend on the mass and speed of an object? And how do relativity and quantum mechanics deal with it? We'll answer all of these questions in this video, in 5 levels of difficulty.
Level 1 - Kinetic energy is the energy that an object has when it is moving. The faster it moves, the more kinetic energy it has. Energy is a quantity or number that we can assign to different parts of whatever we are studying, in order to predict how it should behave at some point in the future (based on Conservation of Energy). Kinetic energy (just like other forms of energy) is measured in Joules.
Level 2 - The formula for kinetic energy is (1/2)mv^2 where m is the mass of our object, and v is its speed. So we find that if we double an object's speed, its kinetic energy increases fourfold. If we double the mass of the object, its kinetic energy increases twofold. It's worth noting that v refers to the speed of the object, not the velocity. In other words, kinetic energy is a scalar.
Level 3 - We've mentioned the speed of an object multiple times here... but what is this speed measured relative to? Whenever we measure the speed of an object, this means the object is moving a certain distance away from some reference point, in every unit of time. From different reference frames, an object may be moving at different speeds. Therefore, these different frames may decide the object has different amounts of kinetic energy. Which is correct? The answer is all of them! Reference frames do not need to agree on how much kinetic energy an object has. As long as the total energy in each frame is conserved, that's all that matters. So to one observer an object may have no kinetic energy, while to another the same object may have kinetic energy... and this is ok!
Level 4 - In special relativity, every object has a certain amount of energy, even when at rest relative to the observer. This energy is given by the famous equation E = mc^2. However when the object is moving, the energy-mass-momentum equivalence equation (a much more complicated one) takes effect. In this video we discuss one of the basic assumptions in special relativity, that the speed of light is constant for all observers. We then also see that the kinetic energy of an object in any reference frame, is the energy it has while moving, minus the energy it had when it was stationary. Upon using a binomial expansion for small velocities, we see that the main (biggest) term of the relativistic kinetic energy equation is the same as the classical, Newtonian kinetic energy equation! However in relativity there are infinitely many terms getting smaller and smaller.
Level 5 - We've only talked about linear kinetic energy so far. We can also consider the rotational kinetic energy of an object when it is undergoing some sort of angular motion. The rotational kinetic energy depends on the angular speed of our object, and on its moment of inertia. The angular speed is simply how much angle is covered by our object per unit time. And the moment of inertia is the equivalent of mass for angular motion. Just like mass is a measure of how hard it is to move an object in a straight line, the moment of inertia is a measure of how hard it is to move it in an angular manner. The moment of inertia depends on both the mass of the object, as well as its shape.
Resources to check out:
Kinetic Energy, Conservation of Energy Different Reference Frames: https://en.wikipedia.org/wiki/Kinetic_energy
Constant Speed of Light: https://en.wikipedia.org/wiki/Speed_of_light
Rotational Kinetic Energy: https://en.wikipedia.org/wiki/Rotational_energy
Moment of Inertia: https://en.wikipedia.org/wiki/Moment_of_inertia
Many of you have asked about the stuff I use to make my videos, so I'm posting some affiliate links here! I make a small commission if you make a purchase through these links.
A Quantum Physics Book I Enjoy: https://amzn.to/3sxLlgL
My Camera (Sony A6400): https://amzn.to/2SjZzWq
ND Filter: https://amzn.to/3qoGwHk
Microphone and Stand (Fifine): https://amzn.to/2OwyWvt
Gorillapod Tripod: https://amzn.to/3wQ0L2Q
Thanks so much for watching - please do check out my socials here:
Instagram - @parthvlogs
Patreon - patreon.com/parthg
Music Chanel - Parth G's Shenanigans
Merch - https://parth-gs-merch-stand.creator-spring.com/
Timestamps:
0:00 - Intro: Kinetic Energy by Parth G
0:31 - Level 1 - What is Kinetic Energy? How do we measure it?
1:37 - Level 2 - The Formula for Kinetic Energy EXPLAINED
3:54 - Level 3 - Kinetic Energy in different Reference Frames!
5:52 - Level 4 - How does Special Relativity deal with Kinetic Energy?
9:54 - Level 5 - Rotational Kinetic Energy, and Quantum Mechanics
12:17 - Thanks for Watching! Please Subscribe for more Fun Physics!
