# Work and Energy of a climbing person

1. Oct 1, 2009

### agadag

1. The problem statement, all variables and given/known data

How many meters above the ground would a person ( 188.3 lb ) have to climb to gain 3 kilojoules ( 3000 joules ) of potential energy. We usually measure our weight ( W = mg ) in pounds. For conversions, you may need to know that 1 pound is equal to 4.448 Newtons.

2. Relevant equations

PE = MGH

3. The attempt at a solution
3000=837.558*9.8*h
I used this to solve for h...not working! please help!

2. Oct 1, 2009

### Andrew Mason

PE = Work done against gravity = $\vec F \cdot \vec d = (mg)h =$ weight x height.

You do not have to use g explicitly here since you are given the weight, in Newtons, of one pound of matter. The person weighs 188.3 times that or, as you have found, 837.558 N.

AM

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