Question

A body A is moving in North direction, while another body B is moving towards South. Velocity of A is greater than that of B. If North is taken as positive, which of the following relative velocities is positive?

(a) Velocity of A with respect to B

(b) Velocity of B with respect to A

(c) Velocity of A with respect to ground

(d) Velocity of B with respect to ground

This question was posed to me in unit test.

My question is taken from Motion in a Straight Line in chapter Motion in a Straight Line of Physics – Class 11

Answer 1

The correct choice is (a) Velocity of A with respect to B

To explain I would say: The formula for relative velocity is, Vector VR = Vector VA – Vector VB. The velocity of A is greater in magnitude hence the relative velocity of A will be positive. The direction of the relative velocity will be Northwards.