How much time will it take for the ball to reach the ground and at what height will the ball be after each second of travel?

4 seconds

It will still take 4 seconds to fall 78.4 meters Use the equation y = 0.5 g t2 and substitute -9.8 m/s/s for g. The vertical displacement must then be subtracted from the initial height of 78. 4 m. At t = 1 s, y = 4.9 m (down) so height is 73.5 m (78.4 m - 4.9 m ) At t = 2 s, y = 19.6 m (down) so height is 58.8 m (78.4 m - 19.6 m ) At t = 3 s, y = 44.1 m (down) so height is 34.3 m (78.4 m - 45 m) At t = 4 s, y = 78.4 m (down) so height is 0 m (78.4 m - 78.4 m) NOTE: the cannon balls horizontal speed does not affect the time to fall a vertical distance of 78.4 m.