If you want to know the friction coefficient for a block on a surface.
1. Put the block on the horizontal surface
2. Raise one end of the surface. record the angle (cta) when the block starts moving
3. the friction coefficient = tan(cta)
Drag the slider on the left to change the angle of the ramp.
Virtual Physics laboratory Original URL
Fu-Kwun Hwang, Dept. Of Physics, National Taiwan Normal University.