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- Jan 29th 2010, 07:32 AMMathhelpzCalc 2: Find the work W required to pump the water out ....
- Jan 29th 2010, 09:48 AMCalculus26
The cross-sections are rectangles all of which are 12 m long and have variable width.

To find the width as a function of y --the height above thr ground use similar triangles.

The distance a cross -section is pumped is 7 -y

The int limits are 0 to 4

See attachment - Jan 29th 2010, 11:32 AMebaines
Don't forget to multiply by

*g*times the densiy of water, which is approximateley 100 Kg/m^3. This gets you the answer in terms of kg-m^2/s^2, or Joules. - Jan 29th 2010, 12:34 PMCalculus26
Thanks--- I was thinking density =1kg/L which is true but as you pointed out the units would have been off.

1kg/L tranlsates to 1000kg/m^3 not 100 - Jan 29th 2010, 12:39 PMebaines
- Jan 29th 2010, 12:44 PMCalculus26
The following attachment reflects the changes-- thanks again