Halfback Tackle
A halfback on an apparent breakaway for a touchdown is tackled from behind. If the halfback has a mass of 97.0 kg and was moving at 3.90 m/s when he was tackled by an 75.2 kg cornerback running at 5.92 m/s in the same direction, what was their mutual speed immediately after the touchdown-saving tackle?
4.78 m/s
4.78 m/s