- #1

SammyLP250

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## Homework Statement

A 1.57 kg brick measures 20.0 cm x 8.00 cm x 5.50 cm. Taking the zero of potential energy when the brick lies on its broadest face. (a) What is the potential energy when the brick is standing on end? Note: You can treat the brick as though all its mass is concentrated at its center. (b) What is the potential energy when it's balanced on its 8 cm edge?

## Homework Equations

U

_{g}=mgh

## The Attempt at a Solution

I could not figure out the first part of the question because I don't know what "standing on end" means.

As for B:

m = 1.57 kg

g = 9.81

h = 0.08 m

U

_{g}= (1.57)(9.81)(0.08) = 1.23 J

That is the answer I get, but Mastering Physics tells me that there was a rounding error and the answer is 1.17 J and I cannot figure out where I was wrong. This is not supposed to be a hard problem. Maybe I'm thinking too hard about it??

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