Question

If a boy on top of a 64 foot tower throws a ball horizontally so that the ball lands 108 feet away, how fast was the ball moving the moment it left his hand?

Answer 1

you'll have to use two equations for this. you have vertical height and horizontal height. We also know the initial velocity in the y direction but not in the x direction and we know acceleration due to gravity is 9.8 m/s/s but we don't know time. use this to solve for t in the y direction. \[d=v_0t+\frac{1}{2}at^2\] the time for the ball to fall down in the y direction is the same as the time it takes to fall in the x direction. knowing that you can use the same value for the next equation which just so happens to be the same equation. now using that time and the known value for the distance traveled in the x direction solve for your initial velocity.