[quote author=Fu-Kwun Hwang link=topic=150.msg6487#msg6487 date=1276159077]
Here is the EJS version of the same applet.
The blue arrow represents the friction force, while red arrow is the velocity vector.
The red trace represents Vx as a function of time Vx(t), while green trace represents of the ping-pong ball.
When equal to Vx, the ping-pong ball become rolling without slipping (And the slide friction disappear).
Click the following image to view the simulation.