A body of mass m moving with a uniform velocity of `40 m s^(-1)` collides with another body of mass m, at rest and then the two together begin to move with a uniform velocity of `30 m s^(-1)` The ratio of their masses `((m_1)/(m_2))` is

Options

A. 0.75
B. 0.33
C. 3
D. 1.33

Answer

C

Explanation

Applying the law of conservation of linear momentum , we get
`m_1 xx 40 + m_2 xx 0 = (m_1 + m_2) 30`
`:. 40/30 = (m_1 + m_3)/(m_1) = 1 + (m_2)/(m_1)`
`:. (m_2)/(m_1) = 40/30 - 1 = 10/30 = 1/3 " or " (m_1)/(m_2) = 3/1`.