How do I find the volume of a described solid using integration?

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To find the volume of a solid using integration, start by visualizing the solid with the x-axis through its center. The integral should be set up from 0 to h, using the formula (pi)(ρ(y))^2, where ρ(y) represents the cross-sectional radius at height y. It is essential to relate the radius ρ to the height h and express it as a function of y. The constants R and r are given in the problem, and the integration should be performed over y, not the constants. This approach will lead to the correct volume calculation.
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Homework Statement


I uploaded of a picture of the question so hopefully it comes up here.

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The Attempt at a Solution



OK! so i am SO confused on where to start.
I am imagining the solid flipped on its side with the x-axis going through its center.

So all i have is that the integral would be from 0 to h of (pi)(r)^2
Is this at all close?
Any hints would be greatly appreciated. :)
 

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That's a start but you have to relate r to h and then integrate over h.
 
r, R and h are given as constants in your diagram. Let's not integrate over any of them. Let y be the distance from the bottom of your solid. So y goes from 0 to h. Then your integral is the integral of (pi)(ρ(y))^2*dy for y from 0 to h. Where ρ(y) is the cross sectional radius of your solid at the height y. ρ(0)=R, ρ(h)=r. Can you figure out an expression for ρ(y) at a general height y?
 
I GOT IT !
thanks for the help dick :)
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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