The net external torque on a system of particles about an axis is zero. Which of the following are compatible with it ?

The sum of all the external forces on a system of particles is zero. Which of the following must be true for the system of particles ?

If the net external forces acting on the system oif particles is zero, then which of the following may vary?

If the net external forces acting on the system oif particles is zero, then which of the following may vary?

If net force on a system of particles is zero, then match the following.

If the external force acting on a system of particle is zero then …………..