When the arm came to a stop at 90 the contents were projected at a horizontal trajectory therefore the velocity calculated above remains constant until the missiles collide with the ground. Once the velocity is determined 2 simple equations can be used to determine time the missiles will hit the ground and the maximum range. As the missiles is shot horizontally the velocity is equal to the horizontal velocity if air velocity is considered negligible there is no change in the velocity of missile until it hits the ground. This means whatever/whomever the missile comes in contact with before the missile lands will be struck at full velocity. The time it takes gravity to bring the missile to the ground depends on the height the missile is launched from (how high in the arm the arm reached).