Question

A small rubber ball is launched by a compressed-air cannon from ground level with an initial speed of 19.8 m/s directly upward. Choose upward as the positive direction in your analysis. (a) What is the maximum height above the ground that the ball reaches

Answer 1

1/2 M v^2 = M g H conservation of energy

H = v^2 / (2 * g) = 19.8^2 / (2 * 9.8) = 20 meters

Also, T = 19.8 / 9.8 = 2.02 sec to top

H = v0 T - 1/2 g T^2

H = 19.8 * 2.02 - 1/2 * 9.8 * 2.02^2 = 20 meters