Question

In an elastic collision between two particles

• A. net kinetic force is zero
• B. the kinetic energy of the system before collision is equal to the kinetic of the system after collision
• C. linear momentum of system before collision = linear momentum after collision
• D. the total energy of the system is never conserved

Answer 1

Answer: (A), (B), (C)

The correct options are
A net kinetic force is zero
B the kinetic energy of the system before collision is equal to the kinetic of the system after collision
C linear momentum of system before collision = linear momentum after collision

We know,

Net Kinetic force involved in the collision is zero in case of elastic collision.

And as there is no net Kinetic force, net work done during collision=0,

And hence $\Delta KE=0$ during collision.

Hence there is no change in KE before and after collision.

And as there is no external force involved in collision,

Momentum of the colliding system is conserved.

And hence total momentum before collision=total momentum after collision.

Note; momentum is conserved irrespective of elastic/inelastic collision.

Option $\text{A,B,C}$ is correct answer.