Q. A worker stands still on a roof sloped at an angle of 21° above the horizontal. He is prevented from slipping by a static frictional force of 400 N. Find the mass of the worker.
Q. A parachutist descending at a speed of 20.0 m/s loses a shoe at an altitude of 60.0 m. (Assume the positive direction is upward.)
(a) When does the shoe reach the ground?
(b) What is the velocity of the shoe just before it hits the ground?