A ball is thrown down at 72 km h^-1 speed from the top of a building. The building is 125 metres tall. The distance travelled before it reach the ground is as follows, s = u_0 t + 1/2 gt^2 where: u_0 = initial velocity (ms^-1) g = acceleration due to gravity (10 m s^-2) t = time (s). (a) Find the time for the bail to drop to a fifth of the height of the building. (b) Find the time for the bail to reach the ground.
