Emptying a Bowl: Calculating Work

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SUMMARY

The discussion focuses on calculating the work done to empty a hemispherical bowl with a radius of 8 inches, filled with punch weighing 0.04 pounds per cubic inch, to within 2 inches of the top. The correct approach involves using the formula for work, defined as the product of force (weight) and displacement. The weight is calculated using the equation weight = (0.04)(π * r²)dx, leading to the total work being represented by the integral from 2 to 8 of (0.04π)(x)(64 - x²)dx. This method accurately accounts for the displacement and weight of the liquid being pumped over the rim.

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Homework Statement



A hemispherical bowl with radius 8-inches is filled with punch (weighing .04 pound/in^3) to within 2-inches of the top. How much work is done emptying the bowl if the contents are pumped just high enough to get over the rim?

Homework Equations




The Attempt at a Solution



Work = Force(weight)* displacement.

i said displacement was "x"
and for the weight:
r = sqrt(64- x^2)
weight = (.04) (pi * r^2)dx

and so, work to lift weight at a given "x"
is weight*displacement

so i get total work is

integration from 2 to 8 of

(.04pi)(x)(64 - x^2)dx

Is this the right way to approach this problem?
 
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Is it being pumped from underneath so that there is free space between the liquid and the bowl?
 
Yes, that is exactly right!
 

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