1. The problem statement, all variables and given/known data A small ball of mass m is dropped at a height of 50 metres. At the same time, a second ball with twice the mass of the first one is launched at an initial velocity of 10m/s from the ground. Where is the centre of gravity in this system? 2. Relevant equations 3. The attempt at a solution I dont really know where to begin on this one, although i know that the cener of mass will probably lie closer to the ground because of heavier ball. All help is appreciated, thanks in advance.