A bug is 12 cm from the center of a turntable that is rotating with a frequency of 45 rev/min. What minimum coefficient of friction is required so that the bug stays on the turntable?

Answer 1

R = 0.12 m
omega = 45 rev/min *1 min/60s * 2 pi radians/rev= 4.71 rad/s
Ac = R omega^2 = 2.66 m/s^2
m Ac = mu m g
so
mu = Ac/g = 2.66/9.81

Answer 2

A machine of a 100N from a distance 10N is use to move another force 500N to distance 10M.calculate the efficiency of machine