Question

In an elastic collision between two particle :

• A. the total kinetic energy of the system is always conserved.
• B. the kinetic energy of the system before collision is equal to the kinetic energy of the system after collision.
• C. the linear momentum of the system is conserved.
• D. the mechanical energy of the system before collision is equal to the mechanical energy of the system after collision.

Answer 1

Answer: (B), (C), (D)

The correct options are
B the kinetic energy of the system before collision is equal to the kinetic energy of the system after collision.
C the linear momentum of the system is conserved.
D the mechanical energy of the system before collision is equal to the mechanical energy of the system after collision.

Total kinetic energy of the system is not conserved always.

Total kinetic energy of a system is conserved just before and after the collision only in case of perfectly elastic collision.

According to law of conservation of momentum, total linear momentum of the system is always conserved irrespective of elastic or inelastic collision

According conservation of energy, total mechanical energy of a system is always conserved irrespective of elastic or inelastic collision.

Hence total mechanical energy of the system before collision is equal to the mechanical energy of the system after the collision.