A 10-ft trough filled with water has semicircular cross section of diameter 4 ft. How much work is done in pumping all the water over the edge of the trough? Assume that water weighs .

lb.ft.

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- August 27th 2006, 09:53 AMYogi_Bear_79Chk Anwser - How much work is done.....
A 10-ft trough filled with water has semicircular cross section of diameter 4 ft. How much work is done in pumping all the water over the edge of the trough? Assume that water weighs .

lb.ft. - August 27th 2006, 10:15 AMCaptainBlackQuote:

Originally Posted by**Yogi_Bear_79**

So the volume of a layer of thickness below the rim is:

and so its mass is:

.

The work needd to lift this mass to the height of the rim is:

.

So the total work is:

RonL - September 5th 2006, 02:50 PMYogi_Bear_79
I know I am missing something, but by Captain Black's anwser I come up with work done?

- September 5th 2006, 03:35 PMtopsquarkQuote:

Originally Posted by**CaptainBlack**

To continue:

Let z = x^2. Then dz = 2x dx.

Now let y = 4 - z, so dy = -dz.

ft lbs.

-Dan