Two football players collide head-on in midair while chasing a pass. The first player has a 91.0 kg mass and an initial velocity of 5.70 m/s, while the second player has a 123 kg mass and initial velocity of -3.8 m/s. What is their velocity (in m/s) just after impact if they cling together? (Indicate the direction with the sign of your answer.) e