Question

Which of the following is correct for an inelastic collision.
A. The velocity of both the particles may be the same after the collision
B. The kinetic energy is not conserved
C. The linear momentum of the particle is conserved
D. The velocity of separation will be less that velocity of approach

Answer 1

Hint- In an inelastic collision only momentum is conserved kinetic energy is not conserved. So, we cannot apply the law of conservation of kinetic energy in the case of inelastic collision
The kinetic energy is not conserved because some of the energy is transformed into some other forms like heat, sound etc. due to the presence of friction. Hence the total kinetic energy before and after collision will not be the same. There will be a loss in energy
The momentum is always conserved whether the collision is elastic or inelastic

Step by step solution:
In an elastic collision kinetic energy and momentum are conserved. But in an inelastic collision only momentum is conserved kinetic energy is not conserved. So we cannot apply the law of conservation of kinetic energy in the case of inelastic collision. Most of the collisions that happen are inelastic.
The kinetic energy is not conserved because some of the energy is transformed into some other forms like heat, sound etc. due to the presence of friction. Hence the total kinetic energy before and after collision will not be the same. There will be a loss in energy. For example, in the case of a car crash the collision is inelastic. Hear the kinetic energy of the car is converted into heat sound and some energy is used for deforming the shape of the car.
 A perfectly inelastic collision is a collision in which particles stick together after collision. In such cases we can say that the final velocity of both the particles which collided will be the same. But for the cases of inelastic relations which are not perfect the final velocities of the bodies may not be the same and the velocity of separation will be less than the velocity of approach.
The momentum is always conserved whether the collision is elastic or inelastic so we can say that linear momentum of the particle is conserved.

So, option C is correct.

Note: If it is specified that the collision is perfectly inelastic. Then the answer to the question will differ. In perfectly inelastic collisions the particles will stick together after collision. Hence their velocity will be the same after collision. But in the case of other inelastic collisions which are not perfect this condition does not exist.