Why can you just simply assume that you are working with 1 mol of air? This doesn't seem quite right to me...
Edit: Well, I completed it without assuming 1 mol, and had the same answer as you did, so apparently you can. Is this since the only important thing here are ratios and not actual values?
Are you sure about that? Then the problem will state that "An equal ball B is thrown simultaneously" but I'll try that out and see where it takes me. Thanks.
Homework Statement
A ball A is dropped from the top of a building of height h and simultaneously a ball B is thrown upwards and both balls collide. After the collision the ball A has the double the velocity of ball B
Determine the fraction of the building where the balls collide...