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

Zero, a hypothetical planet, has a mass of 5.0*10^23 kg, a radius of 3.0*10^6m, and no atmosphere. A 10kg space probe is to be launched vertically from its surface. (a) If the probe is launched with an initial energy of 5.0*10^7 J, what will its kinetic energy be when it is 4.0*10^6m from the center of Zero? (b) If the probe is to achieve a maximum distance of 8.0*10^6m from the center of Zero, with what initial kinetic energy must it be launched from the surface of Zero?

2. Relevant equations

[tex]U = -\frac{GMm}{r}[/tex]

[tex]U_f + K_f = U_i + K_i[/tex]

3. The attempt at a solution

For part a I attempted to find the potential energy while the probe was on the surface of the planet then find the final potential energy when the probe is at the correct distance then since I knew the total energy and the gravity force is conservative I though I'd use conservation of energy and find the change in potential energy and use that to somehow find K, but it didn't work and I'm clueless...

For part b I don't even know where to begin...

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# Homework Help: Energy and Gravitation

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