Question

A particle of mass m moving towards the east with speed v collides with another particle of the same mass and same speed v moving towards the north. If the two particles stick to each other, the new particle of mass $2m$ will have a speed of?

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

Answer 1

Answer: (C)

$\frac{v}{\sqrt{2}}$

New momentum should be the resultant of individual moment. Therefore,
$(2mV{)}^2=(mv{)}^2+(mv{)}^2$
or $V=\frac{v}{\sqrt{2}}$.