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Calculus/Good help in past,could you help with another

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Expert: - 10/7/2008


Question
A conical tank is 14 ft. across the top and 12 ft. deep. Water is flowing in at
the rate of 30 cu. ft./min and flowing out at the rate of 20 cu. ft./min. How fast is
the surface of the water rising when it is 6 ft. high?

Answer
Since it's flowing in at 30 and out at 20, the net flow is in at
30-20=V.

The surface area A=πrē where r is the radius at the top.

If there are 6 feet in the tank, the water is 7 feet across, so the radius is r=3.5 ft.

Now that you have seen how to compute V (1st paragraph), A(second paragraph), and r, A can be found.

If the net flow in is V and the surface area is A, V/A is the rate of change of depth.

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Any kind of calculus question you want. I also have answered some questions in Physics (mass, momentum, falling bodies), Chemistry (charge, reactions, symbols, molecules), and Biology.

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Experience in the area: I have tutored students in all areas of mathematics for over 25 years. Education/Credentials: BSand MS in Mathematics from Oregon State University, where I completed sophomore course in Physics and Chemistry. I received both degrees with high honors. Awards and Honors: I have passed Actuarial tests 100, 110, and 135.

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