A proton collides with a neutron (mass almost identical to the proton) to form a deuteron. What will be the velocity of the deuteron if it is formed from a proton moving with velocity $7.0 \times 10^6$ m/sto the left and a neutron moving with velocity $4.0 \times 10^6$m/sto the right?( Proton mass $=1.67 \times 10^{-27}$)