Question

How long will it take for two point masses in a vacuum to collide due to gravity?

Answer 1

I know that \(a = \frac{K}{r^2}\) where \(K\) is just a constant to roll up G and the masses for brevity.

Answer 2

I'm not sure what to do with \(a(r) = \frac{K}{r^2}\)...

Answer 3

You need to do an integral!

Answer 4

I answered this a few days ago for someone else:
http://openstudy.com/users/mrnood#/updates/531a36ffe4b0108f77db0509