simple, succinct, nuanced. this video is amazing. its a shame that most professors cant just be straightforward like this. theyd rather spend 2 minutes teaching it poorly and re-explaining it over and over rather than just putting a good 10 minutes aside to nail the topic. thank you for these videos you are saving my life.

How can an amazing explanation like this get low views. Without any hesitation the best explanation on the topic !!!

@aryensujjan

4 жыл бұрын

truth is always in a hidden dark room so lets lit it up by sharing

@amberheard2869

4 жыл бұрын

Physicist are rare and valuable. If more human will come to this then we will be valueless.

@nanou2

3 жыл бұрын

Shut up clown no one cares

@marrytesfu3163

3 жыл бұрын

@@nanou2 okay

Best explanation on youtube. Thanks MIT❤❤

Literally couldn't be a better use of technology and materials! Amazing explanation.

The best explanation for Inertial frame of reference.

Really neat and clear explanation....

beautifully explained sir!

Thanks MIT.. It's the best explanation of transformation of inertial frame.... But why this videos have this small like?...

Best best.........explanation.

It was clearly explained thanks

excellent sir

thank you

really thank u

wonderful!

amazing 😉

Lovelyyyyyyyy !!!

MIT is improving the world by providing free education. Meanwhile my school doesn't even give students soft copy of our lecture notes and tutorials and doesn't give access to lecture videos of higher order subjects to everyone

Nothing in the universe exists in motion without any forces acting upon it. So, how can you know if Newton is correct? You cannot create an experiment to test it. You can make more and more accurate predictions and measurements, but you will never know for certain because you are using idealized conditions.

Sir in 4:43 you said that r prime will appear to be in motion because the distance between the observers changes. What if the S prime observer is moving in a circular path?

@darrenwey5088

5 жыл бұрын

That would be acceleration and that is now not a constant velocity

@yurisugano6638

4 жыл бұрын

Think of S' moving in a circular path around S. The vector R is also a function of time, R(t) = R0 + wt, where w is the angular velocity. w is a velocity vector perpendicular to R, and its time derivative is an acceleration vector pointing to the origin (centripetal acceleration). If w is constant (as V is in the video), the magnitude of the velocity is constant, but its direction is not. That gives you the velocity (V) and acceleration (A) between the reference frames, with which you can calculate the velocity and acceleration from the second reference frame as done in the video. v' = v - V; a' = a - A. Drawing the vectors will help understand what is happening. Proof requires differentiating trigonometric functions but here it goes: In order to make the math simpler, think of frame S' as always being 1 unit distant from frame S, thus moving at a two-dimensional circular path around S at distance 1. Let R be a vector between the two reference frames, the coordinates of R can be obtained by trigonometry, and are always determined by R(t) = ⟨cos wt, sin wt⟩; the velocity vector can be obtained by the first derivative of the position vector, R'(t) = ⟨- w sin wt, w cos wt⟩. You can further demonstrate they are perpendicular by taking their dot product (which equals 0). Then, the acceleration is the second time derivative of R, R''(t) = ⟨-w^2 cos wt, - w^2 sin wt⟩. Thus the acceleration R''(t) lies in the opposite direction of R(t), and its acceleration is always pointing towards the origin (where frame S is). You can get the magnitude of the vectors by the Pythagorean theorem, and it makes sense that the magnitude of the velocity w is w itself, since that is how we defined it to begin with. The magnitude of the acceleration is w^2.

@slowpoke96Z28

11 ай бұрын

The rigid body appears to be in motion. The r' is a vector that will change. If frame S' moves in a circle, r' & R' will have definable limits as the rigid body just appears to move side to side

anyone clear my doubt please What if the net force on some particle is zero and we choose that particle itself as the reference frame or frame moving uniformly relative to the particle. whether we can call that frame an inertial frame of reference?

@adastra6718

3 жыл бұрын

Well yes

@aryanvardhan809

2 жыл бұрын

Yes, the origin in this example is analogous to a particle

what does it mean if "the coordinate axes in frame S' are parallel to, but displaced away from the coordinate axes in frame S"? Also, is the object moving from the origin of Frame S to where it is shown in the video?

@abcddd580

6 жыл бұрын

also, why wouldn't the position vectors r and r' be the same? Can someone give me a more tangible example with human observers and a moving ball or something like that? Thanks!

@samd3764

6 жыл бұрын

See, think of a reference frame as a stationary position or point of view from which you see an event happening. If you're on earth then since to you the earth appears to be at rest but you observe the sun moving in the sky, then it is logically correct to state that _relative to you_ the earth is at rest while the sun goes around it. Similarly, standing on the sun, you see the earth go round you but the sun is at rest so now, _relative to you (on the sun)_ the earth is moving while the sun is stationary. Remember, all motion is relative so arguing that the earth is _really_ moving is pointless. From one point of view it is, from another, it is not. After you understand the idea of the reference frame just being a view point, you need to know how to describe events mathematically from these different point of views. That's why we use a coordinate axis. The xy axis used here only depicts the position of the object so, those are position vectors and don't depict any movement on the graph. The frame S' being parallel but displaced away from S'' means that only the distance of the object from the origin is different in the frames, not the angle at which they are viewed from the different frames. Something like this files.askiitians.com/cdn1/images/2014917-162118960-6229-capture-new.png Say there's a tree at position (x,y). You are standing 5 meters in front of it. Put an axis in your frame and consider your position to be the origin (0,0) so the tree is 5 m in front of you. Now say your friend is standing 10 m in front of the tree, right behind you. He doesn't use your axis obviously. In his frame, the origin (0,0) will be where he is standing. So from his axis he measures the tree to be at 10 m in front of him, not 5. The tree's position vector r is different in both the frames because you and your friend are using different reference frames to map its position (and hence different origin points). The magnitude is 5 in your frame and 10 in your friend's frame. This is an example of parallel-y displaced frames. I hope I didn't further confuse you.

@abcddd580

6 жыл бұрын

Sampurna Dasgupta thank you so much. Everything clicked when i realized the object was stationary in the first example and that R was a position vector which simply described distance in a certain direction. I thought the ball was moving and so i got confused.

@SKH741

7 ай бұрын

@@samd3764perfect explanation, thanks

I’m really not understand how this system has a acceleration if it is inertial system. Please explain for me ❤

@scc5637

2 ай бұрын

Inertial frame means frame of refrence is not in acceleration. It does not mean that abject can't have acceleration (the acceleration in discussion is of the object not of the frame)

Sir which book you have preferred for this

@mitocw

3 жыл бұрын

The textbook for this course is "Classical Mechanics: MIT 8.01 Course Notes" (PDF - 67.9MB) by Peter Dourmashkin. Specific readings for each assignment are provided in the Readings section. The PDF is available for free from MIT OpenCourseWare, visit ocw.mit.edu/8-01F16. Best wishes on your studies!

@matiyurrahman3549

3 жыл бұрын

@@mitocw Thanks.

@AtulSharma-pz2di

2 жыл бұрын

@@mitocw what if two frames are accelerating or rotating with each other , your suggested book also not have any answer to this , please help !

Thank you Sir. brilliant lesson 👍

I HATE how i can totally understand this conceptually, but the grammar/syntax throws me off lol.

I am confused and no one will help me. (1) I am told there is only ONE type of inertial frame of reference. (2) meaning if i do a physics experiment in ANY inertial frame i will get the SAME RESULTS no matter what inertial frame i am in (3) I am told earth is an inertial frame. (4) I am told being in outer space at a constant velocity is an inertial frame. OK THESE STATEMENTS CONTRADICT ONE ANOTHER !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Because if that were ALL true then that would mean that i could do physics experiments in outer space (at a constant velocity) and then do the SAME PHYSICS EXPERIMENT on earth and get the SAME RESULTS. But that IS NOT TRUE. THAT IS A LIE. If i am in outer space(at constant velocity) and i hold a ball out and let go of the ball with out throwing it or pushing it in any direction the ball will just float there. But on earth if i do the SAME experiment the ball will fall to the ground. So there are (1) more than one TYPE of inertial frames of reference OR (2) earth is NOT an inertial frame of reference. SO WHICH IS IT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Why wont any one answer me???????

@declanwk1

Жыл бұрын

an inertial frame is one in which there are no external forces acting causing accelerations. The earth is not an inertial frame because as you point out there is gravity acting on objects and because it is spinning on its axis and revolving around the sun (amongst other things). We can often approxiamate it to being an inertial frame though. For example if you roll a marble along a table, the reaction force from the table cancels out gravity. You still need to worry about the external force of friction. The other corrections are fairly small, you can measure the accelerations in the lab due to the earth spinning on its axis (for example foucoults pendulum) but they are quite small. Since we cannot do our experiement in outer space, far form sources of gravity, we either make do with the imperfect earth bound laboratory or else most often imagine the force free inertail frame in our head. One of the first peolpe to do this was Newton, which was quite an achievement, since he lived in the 17th Centurty in a world of horse drawn carts where friction dominated interactions.

@Jmmm19

6 ай бұрын

that is simply because earth and outer space are different. Earth has gravity that acts on the ball and outer space does not have any force acting on the ball. Simply put, the are identical reference frames in space but the forces that are acting on your ball and affecting your experiment are different.

How is he writing on the screen? Thats so cool!

@mitocw

5 жыл бұрын

See lightboard.info/ to see how this was done. :)

Hi sir, I am a mathematics student who are interested in the concepts of spacetime in relativity theory and quantum mechanics with a rigorous mathematical background. Recently I've been self-studying the topic of spacetime in relativity theory, and the first thing to understand clearly is the inertial frames. So I started with ithe nertial frames in Galileo-Newton classical mechanics. In the book "An Introduction to Riemannian Geometry With Applications to Mechanics and Relativity" of authors Godinho - Natário, page 252, they present a definition for inertial frames as follows : " Let M be a smooth manifolds and diffeomorphic to R4. We assume that there exists a special class of diffeomorphisms x : M → R4, p ⟼ x(p) = (t,x1,x2,x3)(p) called inertial frames. A special class of motions is formed by the motions of free particles, i.e. particles which are not acted upon by any external force. The special property that inertial frames have to satisfy is that the motions of free particles are always represented by straight lines. In other words, free particles move with constant velocity relative to inertial frames (Newton’s law of inertia). In particular, motions of particles at rest in an inertial frame are motions of free particles. " What do you think about this definition of inertial frames, is it clear enough to be able to used ? I' haven't got it well yet, I wonder what is the "free particle" is defined by mathmematics in detail ? I know that the if a particle is free in one inertial frame then it is also free in other inertial frames, but I don;t know that is a condition in the definition or it is a theorem ... Because if free particles are defined as the particles under zero external force, then I can give some example of free particles that are not represented bt stright lines in an inertial frames. E.g, let M = R4, consider the diffeomorphism id : M → R4 , id(p) = p, this is a stay put inertial frame. Let a free particle be modeled by the motion α : [0,1] → M, α(s) = (s^2, s, s, s). The motion of this particle in the inertial fram id is given by id ∘ α (s) = α (s) = (s^2, s, s, s). It's clear that the acceleration of this particle is (0,0,0), thus the external force acts upon it is zero, which mean it must be exactly a free particle. But this particle's motion is represented by the curve (s^2, s, s, s) in the inertial frame id, which is not a stright line. May you give me an explanation for my struggling ? Thank you