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Nithya115
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Homework Statement
Forty 2.0kg blocks 20.0cm thick are used to make a retaining wall in the backyard. Each row of the wall will contain 10 blocks. You may assume that the first block is placed at the reference level. How much gravitational potential energy is stored in the wall when the blocks are set in place.
Homework Equations
Eg=mgh
The Attempt at a Solution
To find m (mass):
(40)(2.0kg) = 80kg
To find height (h):
20.0cm = 0.2m
(0.2m)(4)= 0.8m I used 4 because the wall will be four rows high.
Final...
Eg= (80)(0.8)(9.8)
= 627 J
The answer in my book says 240J
[Mentor's note: Thread title changed to reflect actual subject matter of post]
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