A 2kg ball is attached to a ceiling by a 3 m string. The height of the room is 5.4 meters. Acceleration due to gravity is: 9.8m/s^2. What is the gravitational potential energy relative to a point at the same elevation as the ball? Answer in units of J.(adsbygoogle = window.adsbygoogle || []).push({});

The way I set up the problem is:

y=-(5.4-3)=-2.4 meters

m=2kg

g=9.8m/s^2

PE=mgy=(2)(9.8)(-2.4)=-47.04 J.

however, i checked the answer in my book and it wasn't it. :(

anyone can help show me what I did or/understood wrong?

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# Homework Help: Help with a potential energy question

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