A 3.2-kg chunk of wood is pressed between two hands as shown in the diagram. The forces exerted by the hands are perpendicular to the chunk of wood and are horizontal. The coefficient of static friction between the hands and the wood is 0.53.

a) If the elevator is moving upward at a constant speed of 1.6 m/s, find the kinetic frictional force acting on the suitcase.
b) If the elevator is accelerating upward at 1.6 m/s?, find the kinetic frictional force acting on the suitcase
c) If the elevator is accelerating downward at 1.6 m/s3, find the kinetic frictional force acting on the suitcase.