Professor Hwang

In your equations, the change in horizontal momentum is a function of the difference rw - v.  Hence, even if the ball is undergoing topspin, as long as the angular velocity converted to liner is less than the linear velocity, the result will be a negative change in momentum.  Thus, it seems the linear velocity will then [i]decrease[/i]: v + delta_p/m < v.  It also suggests that if Rw and v are exactly the same in magnitude but opposing in sign, there will be no change in either angular or linear velocity.

Intuitively, the decrease in angular velocity and increase in linear velocity should be tied to the coefficient of friction, but this is used nowhere in this formulation.  How is it not being used?

What am I missing here?  Thanks for helping me understand.

Thanks.