Whenever an object strikes a stationary object of equal mass
Total energy is necessarily conserved
The correct options are (A), (B), (C) and (D)
During the collision, the colliding objects will exert equal and opposite forces on each other due to interaction.
Hence, both the objects will experience equal and opposite momentum as a result of the collision.
(A) When an object collides momentum is conserved. When objects stick together and move, they will have a net final momentum that will be equal to the initial momentum. Option A can be correct.
(B) If kinetic energy is also conserved during the collision, we can say it is an elastic collision. Option B may be correct.
(C) In all collisions, momentum conservation is required. Hence option C is correct.
(D) If the collision is elastic, the total energy is also conserved. Option D is correct.
Thus all options (A), (B), (C), and (D) are correct