A ball is thrown down from the top of a building with a speed of 19.6m/s. The top of the building is 39.2m above the level of the sidewalk. The ball needs 1.46s to travel from the top of the building to the sidewalk. What is the velocity of the ball just before the ball reaches the sidewalk?

Answer 1

final KEnergy =initial PEnergy+initialKEnergy
1/2 m vf^2 = mg*39.2 + 1/2 m 19.6^2
solve for vf