Projectile motion of conservation of energy????? I have a problem that is stumping me. A guy throws a ball and wants it to go through a hoop 20 meters away and the hoop is 2 meters taller than from where he released the ball. If the only given info is the angle at which he threw the ball (45 degrees) How do I set up this problem to determine the initial speed at which the ball was thrown to make it go through the hoop. I have no idea how to set it up.