Question

A particle of mass 'm' is moving with horizontal speed 6 m/sec as shown in figure. If m << M, then for one dimensional elastic collision, the speed of lighter particle after collision will be

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

Answer 1

The correct option is A

2m/sec in original direction

$v_1=\left(\frac{m_1-m_2}{m_1+m_2}\right)u_1+\frac{2m_2{u}_2}{m_1+m_2}Substituting{m}_1=0,v_1=-u_1+2u_2\Rightarrow v_1=-6+2\left(4\right)=2m/s$

i.e. the lighter particle will move in original direction with the speed of 2 m/s.