Underline the correct alternative :- The rate of change of total momentum of a many-particle system is proportional to the external force`//`sum of the internal forces on the system.

Underline the correct alternative :- When a conservative force does positive work on a body, the potential energy of the body increases//decreases//remains unaltered .

Underline the correct alternative :- In an inelastic collision of two bodies, the quantities which do not change after the collision are the total kinetic energy//total linear momentum//total energy of the system of two bodies.

Can KE of a system be increased or decreased without the application of external force?

The centre of mass of a system of particles moves as if all the _________ of the system was concentrated at the _________ of mass and all the external forces acting on the system were applied directly at this point.

When brakes are applied in a car,the brake-shoes apply frictional force on the wheels.these forces are internal for the system(car).For retardation,external forces ust act on the system.The force of friction at the road surface remains the same before and after teh brakes are applied (f = mu N) .How does the car stop?

State if each of the following statements is true or false. Give reasons for your answer:- Total energy of a system is always conserved, no matter what internal and external forces on the body are present.

An electron and a proton are moving under the influence of mutual forces. In calculating the change in the kinetic energy of the system during motion, one ignores the magnetic force of one on another. This is because.