The rectangular tank shown here, with its top at ground level, is used to catch runoff water. Assume that the water weighs 62.5lb/ft3.a. How much work does it take to empty the tank by pumping the water back to ground level once the tank is full?b. If the water is pumped to ground level with a (10/11)-horsepower (hp) motor (work output 500ft−lb/sec), how long will it take to empty the tank (to the nearest minute)?c. Show that the pump in part (b) will lower the water level 10ft (halfway) during the first 18 minutes of pumping.d. What are the answers to parts (a) and (b) in a location where water weighs 62.31lb/ft3?62.61lb/ft3?a. Set up an integral to find the work done.W=□How much work does it take to empty the tank?□□b. How long will it take to empty the tank?□ minutes (Round to the nearest minute as needed.)c. How much work does it take to lower the water level halfway?□□
Q. The rectangular tank shown here, with its top at ground level, is used to catch runoff water. Assume that the water weighs 62.5lb/ft3.a. How much work does it take to empty the tank by pumping the water back to ground level once the tank is full?b. If the water is pumped to ground level with a (10/11)-horsepower (hp) motor (work output 500ft−lb/sec), how long will it take to empty the tank (to the nearest minute)?c. Show that the pump in part (b) will lower the water level 10ft (halfway) during the first 18 minutes of pumping.d. What are the answers to parts (a) and (b) in a location where water weighs 62.31lb/ft3?62.61lb/ft3?a. Set up an integral to find the work done.W=□How much work does it take to empty the tank?□□b. How long will it take to empty the tank?□ minutes (Round to the nearest minute as needed.)c. How much work does it take to lower the water level halfway?□□
Determine Tank Dimensions and Water Weight: Determine the dimensions of the tank and the weight of the water. Assume the tank is a rectangular prism with dimensions 20ft (length) ×10ft (width) ×20ft (depth). The weight of water is given as 62.5lb/ft3.
Calculate Volume of Water: Calculate the volume of water in the tank when full. Volume = length×width×depth=20ft×10ft×20ft=4000ft3.
Calculate Total Weight of Water: Calculate the total weight of the water in the tank. Total weight =volume×density=4000ft3×62.5lb/ft3=250,000lb.
Set up Integral for Work Done: Set up the integral for work done to pump the water to ground level. Work W = ∫020(weight of water per layer×distance to pump)dx, where x is the depth from the top.
Simplify Integral: Simplify the integral. Assume each layer of water is 1ft thick, so the weight of each layer is 62.5lb/ft3×200ft2=12,500lb. The distance to pump each layer is xft. W=∫020(12,500lb×xft)dx.
Calculate Integral: Calculate the integral. W=12,500lb∫020xdx=12,500lb×[2x2]020=12,500lb×(200)=2,500,000ft-lb.
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