Zack pushes a 5-kg block up a 30°-ramp with an applied force F directed towards the top and parallel to the surface of the ramp.
(b) What value of the applied force is needed to move the block down the ramp at a constant speed of 0.5 m/s.
(c) What value of the applied force is needed to move the block up the ramp at an acceleration, a = 0.12 m/s2.