Two bodies of same mass undergoes head on elastic collision then

In one dimensional collision if we consider masses are same 

Then the velocities interchanged and their speeds are interchanged momentum also 

interchanged. In that the faster body slows down and the slower body speeds up when the  m₁ = m₂ = m.

$\text{ Because, head on elastic collision }\mathrm{\&}{\mathrm{m}}_1={\mathrm{m}}_2$

$\begin{array}{r}{v}_1=\left(\frac{{\mathrm{m}}_1-{\mathrm{m}}_2}{{\mathrm{m}}_1+{\mathrm{m}}_2}\right)u_1+\left(\frac{2{\mathrm{m}}_2}{{\mathrm{m}}_1+{\mathrm{m}}_2}\right)u_2\\ v_2=\left(\frac{2{\mathrm{m}}_1}{{\mathrm{m}}_1+{\mathrm{m}}_2}\right)u_1+\left(\frac{{\mathrm{m}}_2-{\mathrm{m}}_1}{{\mathrm{m}}_1+{\mathrm{m}}_2}\right)u_2\end{array}$

So we get their velocities, momenta and speeds are interchanged.

$\begin{array}{r}{v}_1=u_2\\ v_2=u_1\end{array}$