Statement - 1 : Sum of work done by the Newton’s 3rd law pair internal forces, acting between two particles may be zero. Statement -
2 : If two particles undergo same displacement then work done by Newton’s 3rd law pair forces on them is of opposite sign and equal magnitude.

Statement -1: The work done by all forces on a system equals to the change in kinetic energy of that system . This statement is true even if nonconservative forces act on the system. Statement -2: The total work done by internal forces may be positive.

Statement -1: The work done by all forces on a system equals to the change in kinetic energy of that system . This statement is true even if nonconservative forces act on the system. Statement -2: The total work done by internal forces may be positive.

Statement I: In a circular motion, work done by centripetal force is not always zero. Statement II: If speed of the particle increases or decreases in circular motion, net force, acting on the particle is not direction towards the centre.

Statement-1: Non zero work has to be done on a moving particle to change its momentum. Statement-2 : To change momentum of a particle a non zero net force should act on it.

STATEMENT-1 : Acceleration of a particle in a reference frame may be non- zero , even if net external force acting on the particle is zero. and STATEMENT : 2 In a non- - inertial reference frame, Newton's second law is not valid.

STATEMENT-1 : Acceleration of a particle in a reference frame may be non- zero , even if net external force acting on the particle is zero. and STATEMENT : 2 In a non- - inertial reference frame, Newton's second law is not valid.

STATEMENT-1: Work done by the net force acting on a particle is equal to the change in its kinetic energy. STATEMENT-2: Change in potential energy is always equal to the work done by external forces. STATEMENT-3: Work energy theorem is not applicable, if the work is done by the non-conservative forces

STATEMENT-1: Work done by the net force acting on a particle is equal to the change in its kinetic energy. STATEMENT-2: Change in potential energy is always equal to the work done by external forces. STATEMENT-3: Work energy theorem is not applicable, if the work is done by the non-conservative forces

(A) : Acceleration of centre of mass depends only on the external force not on the internal forces. (R ) : Internal forces are the force exerted by the particles on one another according to Newton.s third law they constitutes action, reaction pair and cancel each other.