Ball and relative motion

[GibbsHelmholtz]

What do you mean? Friction is cause of stopping rotation, not the contrary. If you mean that there must be a cause of motion because there is friction and the cause have to overcome the friction, I agree.
Now, back to the reason of this question. If you take a photo at t and another at t+1 and you see the same state, then your system is not closed (it has radiated the heat from friction). If it is closed the photo of the state of the system shows that the temperature has increased between t and t+1, the state has changed. This is what I said in Reply #51.

In that case, you're correct.


I think I want to make clear on the other post for Harvey.  The ball moving right relative to the earth, but moving left relative to the surface when the surface pull to the right. 

[GibbsHelmholtz]

I saw a PHUN simulation Harvey did that illustrate this.


http://www.youtube.com/watch?v=3ToZp4LMQvc&feature=related

The object has both linear and rotational energy after being hit/pull.