A wheel of mass 2 kg having practically all the mass concentrated along the circumference of a circle of radius 20 cm, is rotating on its axis with an angular velocity of 100 rad/s. The rotational kinetic energy of the wheel is
4 J
70 J
400 J
800 J
As we learnt in
Kinetic energy of rotation -
- wherein
= moment of inertia about axis of rotation
= angular velocity
Option 1)
4 J
This solution is incorrect
Option 2)
70 J
This solution is incorrect
Option 3)
400 J
This solution is correct
Option 4)
800 J
This solution is incorrect