A particle of mass `m` moving with horizontal speed `6 m//s` as shown in the figure. If `m lt lt M` then for one - dimensional elastic collision , the speed of lighter particle after collision will be

Options

A. 2m/sec in original direction
B. 2 m/sec opposite to the origin
C. 4 m/sec opposite to the original direction
D. 4 m/sec in original direction

Answer

A

Explanation

`m_1 = m, u_1=6m//s, m_2 = M, u_2 =4m//s`
`v_1=((m_1-m_2)/(m_1+m_2))u_1=(2m_2u_2)/(m_1+m_2)=-u_1+2u_2`
`implies -6 + 8 = 2m//s " " [:. "As" m_1/m_2lt ltlt1]`