A table tennis ball has a diameter of 38 mm and a weight of 0.0245 N. A player hits the ball horizontally at a speed of 10 m/s. Obviously, if the player puts no spin on the ball, it will have a trajectory curved downwards, due to gravity. Compute the amount of backspin (angular velocity) that the player must give to the ball so that it will move horizontally. Is this value realistically possible? Also compute the drag on the ball.

Contributed by Stavros Tavoularis, Department of Mechanical Engineering, University of Ottawa, Ottawa, Canada.