Additional Work problems. 1) A cylindrical water tank 12 feet high with a radius of 8 feet is buried so that the top of the tank is 3 feet below ground level. How much work is done in pumping a full tank of water up to ground level? (The water weighs 62.4 pounds per cubic foot). 15
2
Ans
W
=
π
(8)
∫ (62.4)xdx = 431,308π ft − lb 3
2) A particle is moved along the x‐ axis by a force that measures 8/(1 + x)2 pounds at a point x feet from the origin. Find the work done in moving the particle from the origin to a distance of 12 feet. 12
Ans : W =
8
∫0 (1 + x )2 dx = 7.38 ft − lb