posted by luis .
A water-skier is being pulled by a tow rope attached to a boat. As the driver pushes the throttle forward, the skier accelerates. A 83.0-kg water-skier has an initial speed of 5.9 m/s. Later, the speed increases to 11.4 m/s. Determine the work done by the net external force acting on the skier.
Well, we can get the change in kinetic energy which is the net work done. This is greatly simplified because most of the actual (not net) work done by the tow boat is wasted in wave and frictional drag: (Thrust - Drag = net force = m a)
Work = (1/2)(83)(11.4^2 - 5.9^2)