A large balloon filled with air is dropped from the ceiling of a school lab to the floor about 10 m below. Assume the resistance by air to the motion of the balloon is negligible and the gravitational acceleration is 9.8 m/s^2.
The velocity of the balloon after time t is given by v = u + a*t, where u = 0 m/s as the balloon was initially at rest and a = 9.8 m/s^2.
v = 9.8*t^2
The variation of velocity of the balloon with time is shown in the following graph where the velocity is plotted on the y-axis and the time on the x-axis.