Consider the following two statements (A) Linear momentum of a system of particles is zero (b) Kinetic energy of a system of particles is zero' Then

If the vector sum of the velocities of the particles of a system is zero , then linear momentum of the centre of mass of the system is also zero, but kinetic energies of the particles are not zero .If kinetic energy of a system of particles is zero then the particles must be at rest and in that case linear momentum of the system must be zero.Hence option (4) is right .