- #1

Heisenberg7

- 99

- 18

Let's imagine an object on an inline, in our case, let it be a ball (look at the picture). For the first case, let's assume that the coefficient of friction between the ball and the ground is 0. Would the ball start to roll or would it just slide down the incline without any rotation? Personally, to me, the second case seems a bit counterintuitive, but that's the answer I got from the physics community above. The reason why it seems a bit counterintuitive is this: If we put the ball on the incline, the center of mass of the ball would lose support thus it will cause torque about the lowest point (due to gravity) which would cause the whole ball to rotate. Now, I'm not sure if this is the case, this is what I supposed would happen by pure intuition.

For the second case let's assume that there is friction. If my supposition is correct, how would the torques relate? Now, this is probably a bit of an undefined question. Torque due to friction about the lowest point would be 0 since ##r = 0##. And if my supposition is not correct (also why), what would be the work done by torque (assuming there is friction)?