Question

One end of a string of length l is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v the net force on the particle (directed towards the centre) is

(A) T

(B) T - \(\cfrac{m\text v^2}l\) 

(C) T + \(\cfrac{m\text v^2}l\) 

(D) 0

Answer 1

Correct option is (A) T

The particle is performing circular motion and is constantly accelerated. Hence, it is under the action of external force. As the motion here is confined to horizontal plane, net force on the particle is T.