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bopll
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Homework Statement
A water tank is in the shape of a half cylinder sitting on its side (not its top or its bottom). Let the radius be 10 ft and let the side-lenth on the floor be 30 feet. What should be the water height, measured from the floor up, so that the water tank is half full?
Homework Equations
Volume of a cylinder- h*(pi)r^2
The Attempt at a Solution
First i found the volume needed, which is (30)*(10)^2*pi/2 = 4712.4
Then I tried this problem breaking down rectangular boxes into dy components and set up the integral as follows (using 2sqrt(100-y^2 as the width of the boxes and y as the height of the boxes and 30 being the constant length)
30[tex]\int^{0}_{h}[/tex][tex]\2sqrt{100-y^{2}}[/tex]*2y dy
and set it equal to the needed volume.
I ended up getting 7.7, which i feel is wrong because the height should be less than half of the radius by just thinking about what SHOULD happen.
Should i be taking an entirely different approach to this or what?
ps sorry for the formatting inconsistencies... kinda new here.
thanks guys.
edit: i can't get my bounds right for whatever reason, but i set it from 0 to h.
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