Question

If there is no external force acting on a nonrigid body, which of the following quantities must remain constant
(a) angular momentum
(b) linear momentum
(c) kinetic energy
(d) moment of inertia.

Answer 1

your answer is linear momentum

Answer 2

Answer ⇒ Option (a) and Option (b) .

''Angular momentum and Moment of inertia''.

Explanation ⇒ Assuming that the Angular momentum be L.

∴ External torque = dL/dt

But in the question it is given that it is zero,

∴ dL/dt =0

where, L = a constant.

In the same manner it can be shown that linear momentum will be constant.

Hence, Option (a). and (b). is correct.

Hope it helps.