1. The problem statement, all variables and given/known data A ball is thrown horizontally with speed u from a height of 20m. It hits the ground with a speed 3u. Find the value of u, and the angle at which the ball strikes the ground. 2. Relevant equations The equations of motion. 3. The attempt at a solution I know that I must deal separately with the horizontal and vertical components of the motion. I have worked out that the final vertical velocity will be 19.8m/s but I don't where to go next to find u.