1. The problem statement, all variables and given/known data A ball of mass m = 100g , falls at an height of 5,2m and it collides elastically with the floor and comes up again. Find the height h2 (how much the ball has come up), the impulse, the average force if the collision lasts 0,02seconds. 2. Relevant equations 3. The attempt at a solution I got the velocity just before the collision: mgh = 1/2mv^2 => v = square root of (2gh) => v = 10m/s. Okay, now I don't understand how I can find the height. If it was a completely elastic collision it'd still be 5,2 meters, but I guess it's not because it is actually asking to find it. About the impulse and the average force I know how to find them, but I'd need the height first. Thanks.