A body A, of mass m=0.1 kg has an initial velocity of 3 i ms^-1. It collides elastically with another body, B of the same mass which has an initial…

A body A, of mass $\displaystyle m=0.1 \mathrm{~kg}$ has an initial velocity of $\displaystyle 3 \hat{i} \mathrm{~ms}^{-1}$. It collides elastically with another body, B of the same mass which has an initial velocity of $\displaystyle 5 \hat{j} \mathrm{~ms}^{-1}$. After collision, A moves with a velocity $\displaystyle \vec{v}=4(\hat{i}+\hat{j})$. The energy of B after collision is written as $\displaystyle \frac{x}{10} \mathrm{~J}$. The value of $\displaystyle x$ is \_\_\_\_.