Class 11 Physics Rotational Motion

  Questions

1. A disc of metal is melted and a solid sphere is formed. What will happen to the moment of inertia about a vertical axis passing through the centre?
2. What are the unit and dimensions of moment of inertia ? Is it a vector ?
3. Is radius of gyration of the body a constant quantity?
4. What is the rotational analogue of force and mass.
5. Can a body in translatory motion have angular momentum ?
6. Why spin angular velocity of star is greatly enhanced when it collapses under gravitational pull and becomes a neutron star.
7. Why there are two propellers in a helicopter.
8. The moment of inertia and the angular momentum of two bodies A and B are equal then which has a greater kinetic energy ?
9. A canon ball and marble ball roll from rest down and inclined which goes to the bottom first.
10. If the earth were to shrink suddenly what will happen to the length of the day ?

ANSWERS

1. Decrease
2. Kg m², [ M1 L2 T], No.
3. No.
4. Torque and moment of Inertia.
5. Yes
6. Since angular momentum is conserved therefore, as I decrease
   ω increase.
7. For balancing itself
8. (K.E.)B > (K.E.)A
9. Both will reach simultaneously.
10. Decrease