Suppose an adult blue whale is stranded on a beach. The whale, which lies parallel to the shore, is 15 m from water deep enough for it to swim away in. A group of people line up along the side of the whale to push it back into the ocean. If the whale’s weight is 1. 5 × 10 6 N, and the force of friction that must be overcome by the people is 0. 25 times the whale’s weight, how much work must the people do on the whale in order to return it to the ocean?

Answer :

Answer:

W = F x    work done by force F thru distance X

F = w + .25 w = 1.25 w where w is the weight of the whale

x = 15 m       distance the whale must be pushed

W = 1.25 w * x

W = 1.25 * 1.5E6 N * 15 m = 18.75E6 N * 15 m = 2.81E7 joules