A wheel of the radius 0. 4 m can rotate freely about its axis. A string is wrapped over its rim and a mass of 4 kg is hung. An angular acceleration of `8 rad s^(-2)` is produced in it due to the torque. Then, the moment of inertia of the wheel is ( `g = 10 m s^(-2)`)

Options

A. 2kg `-m^(2)`
B. `1 kg -m^(2)`
C. `4 kg -m^(2)`
D. `8 kg -m^(2)`

Answer

A

Explanation

Given, r=04 m , `alpha=8 rad s^(-2)`
`m=4 kg , I=?`
Torque , `tau=I alpha = mgr rArr 4xx10xx0.4=1xx8 rArr I=16/8= 2 kg -m^(2)`