3. A stationary box is kicked down a frictionless ramp. The foot applies a force of 13.5 N along the ramp for 0.250 s for negligible distance. (a) If the box leaves the foot with a velocity of 2.00 m/s, what is the mass of the box? (b) If the height of the ramp is 0.560 m, what is the magnitude of the momentum of the box at the bottom of the ramp? (c) If the box then collides with a perpendicular stop at the bottom of the ramp, and the collision takes 0.135 s, what is the magnitude of the average force applied by the wall? Which direction is the force?