A wheel having moment of inertia `2 kg m^(2)` about its vertical axis, rotates at the rate of `60 rpm` about this axis. The torque which can stop the wheel's rotation in one minute would be

Options

A. `(2pi)/(15)N-m`
B. `(pi)/(12)N-m`
C. `(pi)/(15)N-m`
D. `(pi)/(18)N-m`

Answer

C

Explanation

Given, `l=2kg-m^(2), omega_(0)=(60)/(60)xx2pi" rad s"^(-1),`
`omega=0, t = 60s.`
The torque required to stop the wheet's rotation is
`tau=l alpha=l((omega_(0)-omega)/(t))=(2xx2pixx60)/(60xx60)=(pi)/(15)N-m^(-1)`