Very helpful.Thanks

great video

Hi does anyone know what about points that lie between the COM and the new point through which we define the axis? We must have a vector sum of displacements taking the COM as the origin going on here. So I suppose in a way we could say we are transforming the coordinate system by a translation to the left? And then RCM is a variable vector while d is a vector to the right, and when squaring, we simply take the modulus squared?

@nebpoma

3 ай бұрын

The proof is not comprehensive

so parallel axis theorm is applicable only for Icm and and any other axis

How do they display the professor's writing not backward? Is he in of a green screen and writing on some board that electronically stores what he writes then they add it the writing to the picture?

@krishnadhulipala9861

5 жыл бұрын

He's likely writing on a large glass pane. However, the camera's view of the writing would be mirror-imaged, so they likely flip the video, which produces the desired effect.

how was the expression (sigma)(mj)(rcmj)=0 obtained? where did Dr. Dourmashkin get this?

@serden8804

6 жыл бұрын

I did not understand, too

@KerbalLauncher

5 жыл бұрын

Definition of center of mass.

@comebackata2

4 жыл бұрын

I think i got it! Imagine you have a sphere with the center of mass marked at the middle. To the right of the CM you get +r, to the left of the CM you get -r. Sum them up you get zero.

@shadon_official2510

4 жыл бұрын

comebackata2 doesn’t matter cause you square it anyway. I still don’t see why it’s zero.

@leoliu7492

4 жыл бұрын

@@comebackata2 This is helpful, thanks!

This proof assumes the rigid object is essentially flat, i.e., thin in the dimension perpendicular to the illustrated view.

At 04:46, does that mean that the integral for the y-component also equals zero?

@balkabag250

Жыл бұрын

yes, both x and y components equal zero by the definition of center of mass

Thanks a ton:)

Does the tilt of an axis also influence the body's rotational inertia?

@MJ-ou9ff

Жыл бұрын

Yes it does

well, I think the diagram is not accurate, just the axis does not pass the centre of mass, it should pass the centre of block?

At 4:24 what is that term called? I mean integral of dm*rcom

@5gallonsofwater495

4 ай бұрын

1 year late reply... but in an another video (kzread.info/dash/bejne/oaBlpbGjYK-nc9Y.html), it was written in summation form. its apparently the "definition of the center of mass."

Hi you might be able to help me with this: If I apply the parallel axis theorem to a body of mass m in uniform circular motion around a point a distance r away, then I get the angular momentum of the body about the point is (I + mr^2) omega where I is the body's moment of inertia around its COM and omega is the body's angular velocity around the point. However if we compute the angular momentum by just getting the orbital angular momentum about the point (where the body isn't spinning around its COM), we get r × mv = (mr^2 omega) which is clearly different to what we got above. Can you point out where I might be making a mistake here. Your help is greatly appreciated. Thanks.

@sabith-p.ksachu8358

3 ай бұрын

L = I omega This relation does not always hold true. It only holds true for bodies that are symmetrical with respect to the axis of rotation

@sabith-p.ksachu8358

3 ай бұрын

And secondly both mass are not the same as you have given, In parallel axis theorem we use the total mass of the body and get the total angular momentum of the system we consider Whereas in the 2nd relation u typed, we use that particle's mass and it only gives L of that particle

@markkennedy9767

3 ай бұрын

Hi I'm not sure if those actually address the question but thanks anyway. No I figured out that my concept of spin angular momentum was off. So If I accept that the first scenario has spin angular momentum (like the moon has spin even though it has a half that never faces the earth) then this problem Is resolved since both orbital and spin angular momentum are omega. Thanks.

Why does that middle term go to zero?

@glokta1

5 жыл бұрын

It's the definition of the center of mass

@comebackata2

4 жыл бұрын

I think i got it! Imagine you have a sphere with the center of mass marked at the middle. To the right of the CM you get +r, to the left of the CM you get -r. Sum them up you get zero.

@shadon_official2510

4 жыл бұрын

meep elaborate more

What does that per thing mean

@rehtronicles879

3 жыл бұрын

its actually 'perp' he is just referring that the its the perpendicular distance from the axis

Sir, so does it mean, Earth is in fact, flat?

@user-wn3bo9vo7f

4 жыл бұрын

Precisely

ok

Wonderfull dear

Wow he writes everything mirrored...

@astrosertao

2 жыл бұрын

he writes normally and then mirror the video

Most impressive part is how he can write backwards so quickly. lol

@swaree

3 жыл бұрын

bruh, the image is mirrored