Q.

A constant torque of 100 Nm turns a wheel of moment of inertia 300 kg m2 about an axis passing through its centre. Starting from rest, its angular velocity after 3 s is    [2023]

1 1 rad/s  
2 5 rad/s  
3 10 rad/s  
4 15 rad/s  

Ans.

(1)

With same analogy as F=ma we can write torque as,

  τ=Iα or α=τI=100300=13rad/sec2

Using equation of motion for rotational motion, ωi=0

ωf=ωi+αt=0+13×3

ωf=1rad/sec