A wheel having moment of inertia `2 kg - m^(2)` about its axis, rotates at 50 rpm about the same axis . The torque required to stop the wheel in one minute is

Options

A. `(pi)/(10)Nm`
B. `(pi)/(18)Nm`
C. `-(pi)/(12)Nm`
D. `(3pi)/(8) Nm`

Answer

B

Explanation

Given, moment of inertia of a wheel, ` l = 2 kg-m^(-2)` and angular velocity of wheel,
`omrga = 50 rpm = (50)/(60) xx 2pi =(5)/(3) pi red s^(-1)`
The torque repuired to stop the wheel,
`rArr tau= l alpha = l((omega)/(t))`
`rArr tau = 2 xx ((5//3 pi)/(60)) " "[:.t = 1 min = 60 sec]`
`= (pi)/(18) N-m`