a block sits on a frictionless inclined plane, attached to another block over a frictionless pulley. the angle of the incline is 20 degrees. what is the tension in the rope and the acceleration of the system?

B) what is the speed of the system after the 2kg block has fallen 20cm?
C) Friction is added to the plane so that the acceleration of the system is cut in half. what is the coefficent of friction is required to do this?