In the first case, a ball with a mass m is thrown vertically upward, second case, a ball with the same mass is thrown horizontally, third case, a ball with the same mass is thrown vertically downward, Compare the velocity v when the ball hit the ground for the first, second and third case. If I use conservation of energy to work it, I find that the velocity at the bottom of the ground is the same for each case. However, if I use equation of linear motion, I find that the second case, the ball hits the ground with a velocity smaller than the first and third case. What is wrong??? I'm totally confused.