4) Mass 1 is initially moving at 3 m/s in the +x direction andit collides perfectly elastically with mass 2 moving at 10 m/s inthe -x direction. After the collision, mass 1 is moving at 5 m/s inthe +x direction. What is the final velocity of mass 2 in m/s? Ifin the negative x direction, include a negative sign. (Note: themasses are not needed to answer this question.)
