"A fuel tank is an upright cylinder, buried so that its circular top is 10 feet beneath ground level. The tank has a radius of 5 feet and is 15 feet high, although the current oil level is only 6 feet deep. Calculate the work required to pump all of the oil to the surface. Oil weighs 50 lb/ft^3."(adsbygoogle = window.adsbygoogle || []).push({});

What I did was to first calculate the volume of the oil:

[tex]V=\pi r^{2}h=150\pi[/tex]

Next, I calculated the mass of the oil:

[tex]150\pi*50=7500\pi[/tex]

To figure out the total work, I integrated it with bounds from 0 to 25 because that is how far it would take to get it all to the surface:

[tex]\int_{0}^{25}7500\pi dx=187500\pi\approx 589049[/tex]

The problem I have is that this isn't the answer my book has. It says the answer should be 518363. The only way I get that answer is by making the upper bound 22 rather than 25. Can anyone tell me why it is 22?

Thanks for your help.

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# Homework Help: Total Work (Pumping Oil from a Tank).

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