A ball falls vertically in air from rest. The variation with time 
of the distance 
moved by the ball is shown in the figure below.
By reference to the figure above, explain how it can be deduced that
the ball is initially at rest,
air resistance is not negligible.
Use the figure to determine the speed of the ball at a time of 
after it has been released.
On the figure, sketch a graph to show the variation with time of the distance moved by the ball for negligible air resistance. You are not expected to carry out any further calculations.
.
