Agirl throws a ball of mass 0.8 kg against a wall. the ball strikes the wall horizontally with a speed of 11 m/s, and it bounces back with this same speed. the ball is in contact with the wall 0.05 s. what is the average force exerted on the wall by the ball?

Consider a small frictionless puck perched at the top of a fixed sphere of radius r. if the puck is given a tiny nudge so that it begins to slide down, through what vertical height will it descend before it leaves the surface of the sphere? [hint: use conservation of energy to find the puck's speed as a func e conservation of energy to find the puck's speed as a function of its height at what value of this normal force does the puck leave the sphere? ] here on the puck.