A computer weighing 87 N rests on the horizontal surface of your desk. The coefficient of friction

Question:

A computer weighing 87 N rests on the horizontal surface of your desk. The coefficient of friction between the computer and the desk is 0.60.
(a) Draw an FBD for the computer.
(b) What is the magnitude of the frictional force acting on the computer?
(c) How hard would you have to push on it to get it to start to slide across the desk?