A rock is dropped from outer space (initial velocity=0)(adsbygoogle = window.adsbygoogle || []).push({});

at a radius R from Earth's center. It is recorded moving at a

speed 8368 m/s when it strikes the surface of the Earth. What

was R? (in m) (Ignore the air resistance felt during the last

few miles of the approach to the planet) R earth = 6.38*10^6

m, M earth = 5.98*10^24. (in m)

Not sure about what equation to even start with. Was thinking about

g = (G*M earth)/r^2, but don't know what g is, and I don't see how I can find out without being given a time frame. Anyone know? thanks a lot

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# Homework Help: Radius of earth

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