Spark image

Parabolic trajectory

This animation shows that horizontal and vertical velocities of a falling object are independent. The plane and the train are both moving with the same velocity when a ball is dropped from the plane. It carries on with the same horizontal velocity (ignoring air resistance) but accelerates downwards.

The ball remains vertically below the plane and vertically above the truck, eventually landing in the truck.
© Keith Gibbs/John Bourne 2009