The Total solution for NCERT class 6-12
In which of the following examples of motion, can the body be consideredapproximately 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.
( a ), ( b ) The size ofthe train carriage and the cap is very small as compared to the distancethey’ve travelled, i.e. the distance between the two stations and the length ofthe race track, respectively. Therefore, the cap and the carriage can beconsidered as point objects.
The size of thebasketball is comparable to the distance through which it bounces off afterhitting the floor. Thus, basketball cannot be treated as a point object.Likewise, the size of the bottle is comparable to the height of the chair fromwhich it drops. Thus, the bottle cannot be treated as a point object.