Question

A particle of mass $m$ moving towards west with speed $v$ collides with another particle of mass $m$ moving towards south. If two particles stich to each other, the speed of the new particle of mass $2\, m$ will be

• A. $v \sqrt{2}$
• B. $\frac{v}{\sqrt{2}}$
• C. $\frac{v}{2}$
• D. $v$

Answer 1

Answer: (B)

Using conservation of momentum
$P_{i}=P_{f}$
$m v(-\hat{i})+m v(-\hat{j})=2 m \vec{v}^{1}$
$\left|v^{1}\right|=\frac{v}{\sqrt{2}}$