A point mass of 1 kg collides elastically with a stationary point mass of 5 kg. After their collision, the 1 kg mass reverses its direction and moves with a speed of 2 $$ms^{-1}$$.
Which of the following statement(s) is (are) correct for the system of these two masses ?

A

Total momentumof the system is 3 kg $$ms^{-1}$$

B

Momentum of 5 kg massaftercollision is 4 kg $$ms^{-1}$$

C

Kinetic energy of the centre of mass is 0.75 J

D

Total kinetic energy of the system is 4 J