Two football players collide head on in midair while trying to catch a ball, and they cling together afterward. The first player has a mass of 95.0 kg and an initial velocity of 6.00 m/s, while the second has a mass of 115 kg and an initial velocity of -3.50 m/s. What is their velocity just after impact?

1. Taking the first player's direction as positive, this is a perfectly inelastic collision since the two players cling together. 2. Momentum conservation gives (95.0 kg)(6.00 m/s) + (115 kg)(-3.50 m/s) equal to (95.0 kg + 115 kg) times the final velocity. 3. The left side gives 570 minus 402.5, which is 167.5 kg m/s. 4. Dividing by the combined mass of 210 kg gives a final velocity of about 0.80 m/s. 5. Since this value is positive, the players move off in the first player's original direction, and the momenta clearly do not cancel to exactly zero. _Source: OpenStax College Physics (CC BY 4.0), Ch 8 "Linear Momentum and Collisions", section 8.5 Inelastic Collisions in One Dimension_