A particle undergoes uniform circular motion. About which point on the plane of the circle…

Q:  A particle undergoes uniform circular motion. About which point on the plane of the circle, will the angular momentum of the particle remain conserved ?

(a)Centre of circle

(b)On the circumference of the circle

(c)Inside the circle

(d)Outside the circle

Ans: (a)

Sol: In a uniform circular motion , the force acting on the particle is centripetal force , which is acting towards the centre.
Torque of this force about the centre is zero . hence angular momentum about the centre remain conserved.