A solid homogeneous sphere is moving on a rough horizontal surface, partly rolling and partly sliding. During this kind of motion of this sphere
total kinetic energy is conserved
angular momentum of the sphere about the point of contact with the plane is conserved
only the rotational kinetic energy about the centre of mass is conserved.
angular momentum about the centre of mass is conserved.
As we discussedin
Law of conservation of angular moment -
- wherein
If net torque is zero
i.e.
angular momentum is conserved only when external torque is zero .
Angular momintum absent the pont of contact with the plane remains conseved.
Option 1)
total kinetic energy is conserved
incorrect
Option 2)
angular momentum of the sphere about the point of contact with the plane is conserved
correct
Option 3)
only the rotational kinetic energy about the centre of mass is conserved.
incorrect
Option 4)
angular momentum about the centre of mass is conserved.
incorrect