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Math Help - Calculating Work Help

  1. #1
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    Calculating Work Help

    Hi all, ive ran into a problem with this question, it reads,

    calculate the work against gravity required to build the structure out of brick using the method of examples 2 and 3. Assume that brick has density 80lb/ft^3

    A tower of height 20ft and square base of side 10ft.

    I tried to figure out the work on one small layer, than take the integral from 0 to 20. So i first calculated the volume of each layer which i got 100*delta y, than i got the mass which is 8000, than i calculated the work (9.8)(8000)*delta y i than got F = 78400 delta y. So i tried to integrate that from 0 to 20 but i keep getting the wrong answer, anyone help me out here?
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  2. #2
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    Re: Calculating Work Help

    Quote Originally Posted by kevinnwhat View Post
    Hi all, ive ran into a problem with this question, it reads,

    calculate the work against gravity required to build the structure out of brick using the method of examples 2 and 3. Assume that brick has density 80lb/ft^3

    A tower of height 20ft and square base of side 10ft.

    I tried to figure out the work on one small layer, than take the integral from 0 to 20. So i first calculated the volume of each layer which i got 100*delta y, than i got the mass which is 8000, than i calculated the work (9.8)(8000)*delta y i than got F = 78400 delta y. So i tried to integrate that from 0 to 20 but i keep getting the wrong answer, anyone help me out here?
    what structure? how is it constructed? do you have a picture we can't see?

    one more thing ... you won't be using the value 9.8. you've been given the weight-density of the brick in lbs/ft^3 (English units, not metric) , not the mass density.
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