Two football players are running toward each other. One football player has a mass of 105 kg and is running at 8.6 m/s. The other player has a mass of 90 kg and is running at -9.0 m/s.

Momentum is mass multiplied by velocity, and the players’ momenta point in opposite directions. Their total momentum is (105 kg)(8.6 m/s) + (90 kg)(−9.0 m/s) = 903 − 810 = 93 kg·m/s. The positive result means the total momentum is in the direction of the 105 kg player, so the answer is 93 kg·m/s.

AI-written and checked against the verified answer.