Question

A body of mass 2 kg moving with a velocity of 3 m/sec collides head on with a body of mass 1 kg moving in opposite direction with a velocity of 4 m/sec. After collision, two bodies stick together and move with a common velocity which in m/sec is equal to

• A. $\frac{1}{4}$
• B. $\frac{1}{3}$
• C.
  $\frac{2}{3}$
• D. $\frac{3}{4}$

Answer 1

The correct option is C

$\frac{2}{3}$

$m_1{v}_1-m_2{v}_2=(m_1+m_2)v$

$\Rightarrow (2\times 3)-(1\times 4)=(2+1)v\Rightarrow v=\frac{2}{3}m/s$