Centre of Mass of two Gravitating bodies from rest

[Phillips101]

Hi

How would I show that the centre of mass of two point particles, one of mass m1 and the other m2, when released from rest from infinite simultaneously, stays in the same place?

I feel this is a very simple question, I just can't seem to get it right. Everything I've tried still involves time in it...

Thanks for any help!

 

[peteratcam]

Have you tried conservation of (total) momentum?

 

[Phillips101]

D'oh. I was right, it was very simple. Thanks for that!