Answer thisin 50-60 words. A grinding wheel of mass 5.0 kg and diameter 0.4m is rotating with an angular speed of 2
rev s-1. Calculate the torque which will increase its angular speed to 8 revolution per
second in 2s.

Dear Student
Mass of grinding wheel , m=5 kg
diameter of grinding wheel= 0.4 m
initial angular velocity, w1= 2 rev/sec
final angular velocity,w2=8 rev/sec
time interval from initial to final velocity,t= 2 secs

torque= rotational inertia x angular acceleration

$$\begin{gathered} \tau =I\alpha \\ \alpha =Angual acceleration =\frac{{\omega }_2-{\omega }_1}{t} =\frac{8-2}{2} = 3 rev/s^2 \\ I=\frac{1}{2}m{r}^2 =\frac{1}{2}\times 5\times 0.2\times 0.2=0.1 Kg{m}^2 \\ \tau =I\alpha = 3\times 0.1 = 0.3 N.m \end{gathered}$$

Regards