(a) Two boxes of different mass are at rest on a ramp. What is the minimum coefficient of static friction between the boxes and the ramp if the system is in equilibrium? Given M=(1+0.34)m

(b) Suppose there is no friction between the upper box and the ramp. What is minimum coefficient of friction between the ramp and the lower box is needed for equilibrium?

1 answer

Mass doesn't matter. The angle and the friction coefficient do.