Question

a body of mass 2 kg initially movie with with the velocity of 10 M per second collides with another body of mass 5 kg at rest after collision velocity of a body becomes one metre per second find the velocity of second body

Answer 1

Mass of first body ($m_1$) = 2 kg

Mass of second body ($m_2$) = 5 kg

Initial velocity of 2 kg body ($v_1$) = 10 m/s

Initial velocity of 5 kg body ($v_2$) = 0 m/s

Initial momentum = 2 × 10 + 5 × 0 = 20 kg m/s

Let the velocity of second body be v after the collision

Velocity of first body after the collision is 1 m/s

Final momentum = 2 × 1 + 5 × v

Since, the forces are internal. Hence, the momentum of the system will be conserved.

Initial momentum = Final momentum

2 + 5v = 20

5v =   18

v = 3.6 m/s

Hence, the velocity of the second block is 3.6 m/s