A ball is fired horizontally from a spring gun. At the same time that the first ball leaves the barrel of the spring gun, a second ball is dropped from the same height. Which ball hits the level ground first?

A) The shot ball

B) The dropped ball

C) Both at the same time

D) Need more information

Solution: C. Use the following kinematics equation:

Δy = v_iyΔt + ½a_yΔt²

Δy = 0 + ½a_yΔt²

Δt = √ (2Δy/a_y)

Since the vertical distances and accelerations are the same, they will take the same amount of time to hit the ground.