Lec 24 8.01 Physics I: Classical Mechanics, Fall 1999

Hahhaa. I was just kidding to begin with :D. Wanted a reaction :D hehe

Aha - and now you are looking for an assistant?
Come on. It's O.K. I'll shut up.

I am a Courtesy Clerk at the SuperMarket!

why do you watch this lecture then? knowing such stuff can make you money by the way.
but what do you propose then? What is your profession?

Knowing that doesn't get you paid. LEARN SOMETHING THAT WILL MAKE YOU MONEY!!

Haha, this is definetly a dutch teatcher!! They just can't hide it :D. But it's very interesting!

no - without slip the top is twice as fast as the center.
perhaps you will confirm: the point that has contact with the ground has no velocity at all. vp = 0
Because if it has any horizontal component of velocity it would be "faster" than the ground ->slack.
and this peticular point in contact with the ground at the actual time T: had! vertical velocity downward -deltaT ago and it will have! vert. vel. upwards in +deltaT (for deltaT -> 0 (sec). => vp,vertical(T)=0
Not easy to explain that way.

There's nothing wrong with how he wrote it. If you think only about the top of the circle, it only makes sense that it moves with the same speed as the center. All the other points on the circle must move at that same speed, since the circle does not deform.

very nice lecture anyhow. I guess I'm just used to another way of drafting forces, torque, velocity etc.

...I know what he wants to say. But his draft is at least confusing. He puts two velocities of two different coordinate systems in one draft.

what? vq != vc (in global system)
vq = w*R (of course), but vc of a point (lets say P) on the circle (as it is shown on the blackboard) depends on the angle. vc = 0 when the point P has contact with ground then. And 2Rw at the opposite.

Now I understand how gyroscopes work. He explained this so well, thanks for sharing.

Is that a Dutch teacher? His dialect sounds like mine...

i fail

awesome <3 physicks =)