In which of the following examples of motion, can the body be considered approximately a point object :
(a) a railway carriage moving without jerks between two stations.
(b) a monkey sitting on top of a man cycling smoothly on a circular track.
(c) a spinning cricket ball that turns sharply on hitting the ground.
(d) a tumbling beaker that has slipped off the edge of a table.

Explanation

In (a) and (b), object can be considered as point object. Because the dimensions of the objects can be neglected as compared to distance covered by it.
This condition is not followed in (c) and (d), so it cannot be considered as point object.