(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Find the total gravitational potential energy of the three masses.

2. Relevant equations

U=-GMm/r

3. The attempt at a solution

U between the 10 kg mass & the 20kg mass

-(6.67*10^-11)(20kg)(10kg)/.20 m = -6.67 * 10 ^-8 J

U between the 20kg mass and the 5 kg mass

-(6.67*10^-11)(20kg)(5kg)/.10m = -6.67*10^-8 J

U between the 10 kg mass & the 5 kg mass

-(6.67*10^-11)(10kg)(5kg)/.2236 m = -1.49 * 10^-8 J

adding them up I got -1.483*10^-7 J

but the back of my book says -1.96 * 10^-7 J

Am I doing something wrong?

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# Homework Help: Is my book wrong or am I?

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