$5)$ Mass $1$ is initially moving in the $+$x direction and has $34$ Joules of kinetic energy. It collides perfectly elastically with mass $2$ moving at in the $-$x direction with $20$ Joules of kinetic energy. After the collision, mass $2$ has $30$ Joules of kinetic energy. How much kinetic energy does mass $1$ have after the collision in Joules? $($Note: the masses are not needed to answer this question.$)$