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A point mass of 1kg collides elastically...

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

A

Total momentum of the system is `3 kg ms^(-1)`

B

Momentum of `5 kg` mass after collision 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 `

Text Solution

Verified by Experts

The correct Answer is:
A, C
By conservation of linear momentum

`u=5v-2`……….i
By Newton's experimental law of collision
`u=v+2`…………ii
Using eqn i and ii we have `v=1 m//s` and `u=3m//s`
Kinetic energy of the centre of mass `=1/2m_("system")v_(CM)^(2)=0.75J`
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