A ball is rolling freely on a flat surface

[sganesh88]

If angular momentum wrt to the COM stays the same, the ball's rate of rotation omega stays the same. Since v=omega*r, linear velocity must also remain the same.

If angular momentum wrt to the COM stays the same, the ball's rate of rotation omega stays the same and if the ball is rolling uniformly, i.e., if v=r*omega throughout its motion-this we cannot take for granted- , then yes, the linear velocity remains the same.

 

[Lsos]

Therefore the consensus will be:

The correct answer to the first question is (d), NOT (b)

The correct answer to the second question is (a), NOT (c)

Do we all agree?

I would agree with this. Professors...I've seen a lot of professors be outright wrong in my days. It's a very frustrating situation, because the professor and class end up laughing at YOU, because, after all, how can the professor be wrong?

One professor made the claim that to go fast doesn't require power...just gearing (I'm talking on the Earth in the real world). When I brought up the question of why an aircraft carrier needs a million horsepower, his answer was that acceleration needs power, and an aircraft carrier needs to constantly accelerate to point itself towards the wind.

I was like...ooh.

k.

And yes, he confirmed that the USS Nimitz can go 30 knots through the Atlantic using only a small electric motor and the right gearing :P

Plently of other examples in my college days...