Question

One end of 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. zero
• B. $ T-\frac{m{{v}^{2}}}{I} $
• C. $ T $
• D. $ T+\frac{m{{v}^{2}}}{I} $

Answer 1

Answer: (D)

When particle moves in a circle, then the resultant force must act towards the centre and its magnitude F must satisfy
$ F=\frac{m{{v}^{2}}}{I} $
This resultant force is directed towards the centre it is called centripetal force.This force originates from the tension T
Hence, $ F=\frac{m{{v}^{2}}}{I}=T $