Question

If the resultant force on a system of particles is non-zero, then:

• A. The linear momentum of the system must increase
• B. The velocity of the centre of mass of the system must change.
• C. The distance of the centre of mass may remain constant from a fixed point.
• D. Kinetic energy of all particles must either increase simultaneously or decrease simultaneously.

Answer 1

The correct option is A The linear momentum of the system must increase

It is inertial frame, it means that the frame of reference does not have an acceleration, and so does not have a psudo force

$\sum F=0,=>\frac{dp}{dt}=0$

$p$ is constant

kinetic energy and potential energy does not remain constant

Hence a is the correct answer.