A 50 kg mass is travelling at a speed of 2 m/s. Another 60 kg mass is travelling at a speed of 12m/s in the same direction, strikes the first mass. After the collision the 50 kg mass is travelling with a speed of 4 m/s. The coefficient of restitution of the collision is:

Options

A. `19/30`
B. `30/19`
C. `20/11`
D. `11/20`

Answer

A

Explanation

According to conservation of momentum,
`m_1u_1 + m_2u_2 = m_1v_1 + m_2v_2`
`50 xx 2 + 60 xx 12 = 50 xx 4 + 60 xx v_2`
`v_2 = (62)/6 m//sec , e = (v_1 - v_2)/(u_1 - u_2) = (4 - (62/6))/(2 - 12) = 19/30`