In which of the following exmples of motion, can the body be considered approxinmately a point object :
(a) a railway carriage moving without jerks between two two stations.
(b) a mondey sistting on top of a man cycling smoothly on a circulat track. (c ) a spinning cricket ball that turns sharply on hitting the round . (d) a tumbling beake theat has slopped off the edge of a table ?

Explanation

(a) The size of a carriage is very small as compared to the distance between two stations. Therefore, the carriage can be treated as a point sized object.
(b) The size of a monkey is very small as compared to the size of a circular track. Therefore, the monkey can be considered as a point sized object on the track.
(c) The size of a spinning cricket ball is comparable to the distance through which it turns sharply on hitting the ground. Hence, the cricket ball cannot be considered as a point object.
(d) The size of a beaker is comparable to the height of the table from which it slipped. Hence, the beaker cannot be considered as a point object.