# two spherical balls a and b of masses 2kg and 4kg are moving along same line with velocities 2m/s and 4 m/s respectively .They collide and after collision the second ball moves with a velocity of 1.5 m/s find the final velocity of the first ball

Here in this question the given data is ,

Mass of the first body is 2 kg and second body is 4 Kg.Velocity of the first and second body before collision is 2 m/s and 4 m/s and the velocity of the second body after collision is 1.5 m/s.

Let us take that the velocity of the first body after collision is v' .

Therefore , according to the conservation of Linear Momentum ,

Momentum before collision = Momentum after collision

$\left(2\times 2\right)+\left(4\times 4\right)=\left(2\times v\text{'}\right)+\left(4\times 1\xb75\right)\phantom{\rule{0ex}{0ex}}\Rightarrow 20-6=2v\text{'}\phantom{\rule{0ex}{0ex}}\Rightarrow v\text{'}=\frac{14}{2}=7m/s$

Regards

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