Universal Gravitation Unit



Michael Chin • 2 months, 1 week agologin to reply

I believe that the answer to Question 25 should be U = - G [(Me)(m) r^2]/(Re)^3 which is not on the answer key. The answer given is U = -G [(Me)(m) r^2] / [2 (Re)^3]. This answer makes no sense. When r = Re, we should get the Gravitational PE equation. Instead we get 1/2 the GPE equation.

John Ennis • 2 months agologin to reply

Michael, You are correct, the posted answer is wrong. I redid the problem and got a slightly different answer from what you have - I will neaten it up and email to you to see if you agree. Once we agree on an answer, I'll change the multiple choice selections. Thank you very much for pointing this out. John

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