Assume that you have a rectangular tank with its top at ground level. The length
ID: 2889786 • Letter: A
Question
Assume that you have a rectangular tank with its top at ground level. The length and width of the top are 10 feet and 7 feet, respectively, and the bottom of the tank is 15feet beneath ground level. How much work W does it take to empty the tank by pumping the liquid back to ground level once the tank is full? Assume that the liquid weighs 62 pounds per cubic feet. W = | 6360(11 2-5) ft-lb Note: For this problem a pound is to be taken as a unit of weight (not of mass), so it is not necessary to multiply by the gravitational acceleration constant in order to find the work. Do NOT include units in the box above, or commas in the definitions of large numbers. That is, write 104500 instead of 104,500.)Explanation / Answer
distance of the thin section from bottom = x
area of cross section = 10*7
weight of thin section = 62*10*7 dx
distance the thin section to be moved = 15-x
work rquired ,W=[0 to 15]62*10*7*(15-x) dx
work rquired ,W=[0 to 15]4340(15-x) dx
work rquired ,W=4340(15x-(1/2)x2)|[0 to 15]
work rquired ,W=4340[(15*15-(1/2)152)-(15*0-(1/2)02)]
work rquired ,W=4340*225/2
work rquired ,W=488250 ft-lb