A wheel of radius `0.4m` can rotate freely about its axis as shown in the figure. 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=10m//s^(2)`)

Options

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

Answer

A

Explanation

`tau = Fr_(bot) = 4 xx 10 xx 0.4 = 16N-m`
Now `tau = I alpha rArr I = (16)/(8) =2kg- m^(2)`