An Object of Mass $m_{1}$ Moving in The $+x$ Direction Collides with Another Object at Rest with Mass

An object of mass $m_{1}$ moving in the $+x$ direction collides with another object at rest with mass $m_{2}$ . After the collision, the object with mass $m_{2}$ is observed moving in the $+y$ direction. Such a collision cannot be elastic, no matter what $m_{1}$ and $m_{2}$ might be.