A wheel of moment of inertia `2.0 xx 10^3 kgm^2` is rotating at uniform angular speed of `4 rads^-1`. What is the torque required to stop it in one second.

Options

A. `0.5 xx 10^3 Nm`
B. `8.0 xx 10^3 Nm`
C. `2.0 xx 10^3 Nm`
D. none of these

Answer

B

Explanation

(b) `prop = (omega)/(t) = (4)/(1) = 4 rad//s^2`
`tau = I prop = 2 xx 10^3 xx 4 = 8 xx 10^3 Nm`.