A DVD is dropped from rest. The DVD does not reach terminal velocity before it hits the ground. Explain how the acceleration of the DVD varies from the instant it is dropped until just before it hits the ground.

In the instant when the DVD is dropped, it will have an acceleration of g, with no drag force acting on it as it is not moving. As the DVD accelerates downwards, the drag force acting on it increases and so the magnitude of the net force downwards decreases, decreasing its acceleration. The DVD does not reach terminal velocity, so in the instant before it hits the ground, it will still be accelerating downwards.