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-   -   Setting up a work problem. pumping gasoline (http://www.physicsforums.com/showthread.php?t=177964)

 bakin Jul23-07 12:25 PM

Setting up a work problem. pumping gasoline

I just have a quick question. I'm supposed to find the work required to pump gas out of a cone, but am having trouble finding the radius of the cone.

The cone measures 10 feet in height. I broke it up and set it up using similar triangles, and this is what I got:
http://i8.tinypic.com/4l5h449.jpg
It doesn't seem right though. And, if it is right, where do I go from there? Any help is appreciated :)

 rocomath Jul23-07 12:28 PM

if the height is 10, then y must be the difference from 10, or is that straight from the book?

 bakin Jul23-07 12:31 PM

Ok here is the full problem.

Gasoline weighing 42lb/ft(cubed) is contained in a buried conical tank shown below. (above). Set up an appropriate integral, and find the work required to pump all the gas to ground level.

The tank is 5 feet below ground, i just didn't draw it on the diagram.

edit: so do you think it's 10-y ?

 bakin Jul23-07 12:38 PM

Because 10 is the height of the cone. I'm trying to find the radius of the cone. I know how to do the pumping problems, but I'm just stuck on how to find the radius that you'll end up plugging into the integral.

 bakin Jul23-07 01:20 PM

I don't think I have all the information for the problem. I did a similar problem that gave me the radius of the top of the tank and I was able to do it. I'll check tonight to see if I'm missing something.

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