Recall that work is defined to be force times distance, and that the weight (force) of a liquid is equal to its volume times its density. A fish tank has a rectangular base of width 2 feet and length 6 feet and sides of height 5 feet. If the tank is filled with water weighing 62.5 lb per cubic foot, the work required to pump all the water just over the top of the tank is:

Question

A.) 781.24 ft-lb
B.) 150.0 ft-lb
C.) 9375.o ft-lb
D.) 3750.0 ft-lb
E.) 865.0 ft-lb

Answer 1

9,375

Answer 2

W = 62.5 * 12 integral of (5-y) dy from 0 to 5
Area of each water slice = 12
You have to pump each slice out. An illustration would make you understand better, but I have no way to show you. So, the answer is 9375 lb-ft.