Work done by pumping water into a tank

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jdroidxw
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Homework Statement



Problem with picture attached
I need help on 24. **24 is a continuation of 23 so use the same dimension except for the distance...

Or you can go here http://college.cengage.com/mathemat...alc8e_solution_main.html?CH=00&SECT=a&TYPE=se

Chapter 7, Lesson 5

Homework Equations



Volume=∏r^2*Δy
Water= 9800 N/m^3

∫(Volume)(water)(distance)=Work done ??

The Attempt at a Solution



Volume= 4∏Δy
Weight=9800*4∏Δy
Distance is where I'm not too sure about. Would I use (10-y)??
If so then I got...
∫9800*4∏Δy*(10-y), from 0 to 4 = 1,254,400∏ N-m

My answer looks really huge... Did I mess up anywhere?
 
Attachments
  • Two textbook figures: left, a cylindrical water tank with ground level marked, a 5 - y distance, and a slice at height y; right, the same tank on a tower with a 10 m vertical distance labeled to the stream.
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Welcome to PF, jdroidxw! :smile:

You have the infinitesimal weight correct with 9800*4∏dy.

How far does the water that ends at the bottom have to be pumped up?
And how far does the water that ends at the highest level have to be pumped up?