1. The problem statement, all variables and given/known data A coin is placed 11.0cm from the axis of a rotating turntable of variable speed. When the speed of the turntable is slowly increased, the coin remains fixed on the turntable until a speed of 36rpm is reached and the coin slides off. What is the coefficient of static friction between the coin and the turntable? 2. Relevant equations Normal Force=mg g=9.8 V=(2*pi*r) / T a=(v^2)/r Max static friction=mu*Normal force 11.0cm=0.11m 3. The attempt at a solution Normal force=mg ma=mg a=g 9.8=(V^2)/r 9.8r=(V^2) (9.8)*(0.11)=V^2 V=1.04m/s 1.04m/s=2(3.14)(.11) / T 1.04T=.6908 T=0.6642 I'm stuck and don't know what to do from this point. The max frictional force depends on the normal force, which is equal to mg, so I don't understand how to use the velocity or the T to find Mu, the coefficient? Thank you!