One end of a string of length l is connected to a particle
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:

(i) $T$,

(ii) $T-\frac{m v^{2}}{l}$

(iii) $T+\frac{m v^{2}}{l}$

(iv) 0

T is the tension in the string. [Choose the correct alternative].

solution:

$F=T=\frac{m v^{2}}{l}$