A body of mass $2\,kg$ is moving with velocity $10 \,m/s$ towards east. Another body of same mass and same velocity moving towards north collides with former and coalsces and moves towards north-east. Its velocity is
A body of mass $2\,kg$ is moving with velocity $10 \,m/s$ towards east. Another body of same mass and same velocity moving towards north collides with former and coalsces and moves towards north-east. Its velocity is
$10 \,m/s$
$5\, m/s$
$2.5\, m/s$
$5\sqrt 2 \,m/s$
A body of mass $2\,kg$ is moving with velocity $10 \,m/s$ towards east. Another body of same mass and same velocity moving towards north collides with former and coalsces and moves towards north-east. Its velocity is
Initial momentum = $\vec P = mv\hat i + mv\hat j$
$|\vec P| = \sqrt 2 mv$
Final momentum = $2m \times V$
By the law of conservation of momentum
$2m \times V = \sqrt 2 \;mv$==> $V = \frac{v}{{\sqrt 2 }}$
In the problem $v = 10m/s$ (given)
$V = \frac{{10}}{{\sqrt 2 }} = 5\sqrt 2 \;m/s$
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