posted by Kelly on .
Three identical balls are thrown from a cliff of height, h, above a horizontal plane. One ball is thrown at an angle of 45 degrees above the horizon, the second is thrown horizontally, and the third is thrown at an angle of 30 degrees below the horizon (so, part of this velocity is downward). If all the balls are given the same initial speed, which one will have the greatest speed at the moment just before it hits the ground?
Consider work and energy: The all have the same KE initially, they all gain from gravity the same gPE, so they all have final KE.