Question

Three ants on the floor of a moving bus along a straight line with a uniform speed of 2 cm/s also moves with the same velocity with respect to the ground along the straight line. Then

• A. The collection of three ants can be considered as a rigid body with respect to the bus frame of reference
• B. The collection of three ants can be considered as a rigid body with respect to the ground frame of reference
• C. The collection of three ants is not a rigid body , since they are moving
• D. The first ant can be considered as a rigid body, while the others are moving relative to first ant

Answer 1

The correct option is B The collection of three ants can be considered as a rigid body with respect to the ground frame of reference

A rigid body is an object whose distance between the particles in them are fixed with respect to time. The ants are moving along the straight line with respect to the ground frame of reference and has the same velocity as that of the bus. Thus according to the bus frame of reference, the ants are stationary or the distance between the ants are constant.
Thus, collection of ants can be considered as a rigid body if seen from the bus frame of reference