A body of mass \( 1000 \, \mathrm{kg} \) is moving horizontally with a velocity \( 6 \, \mathrm{m/s} \). If \( 200 \, \mathrm{kg} \) extra mass is added, the final velocity (in \( \mathrm{m/s} \)) is:
\( 3 \)
\( 5 \)
\( 6 \)
\( 2 \)