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 72.0-kg water-skier has an initial speed of 5.10 m/s. Later, while moving along a straight line, the speed increases to 12.1 m/s. Determine the work done by the net external force acting on the skier.

4334.4 J

Explanation:

Work done equals to kinetic energy change

KE=½mv²

Change in KE is given by

∆KE=½m(v²-u²)

Where m is mass of water-skier, KE is kinetic energy, ∆KE is the change in kinetic energy, v is final velocity and u is initial velocity.

Substituting 72 kg for m, 12.1 m/s for v and 5.10 m/s for u then

∆KE=½*72(12.1²-5.10²)=4334.4J

Therefore, the work done by the net external force acting on the skier is equal to 4334.4 J