In an American football game, a 90.4 kilogram fullback running east with a speed of 4.93 m/s is tackled by a 94.1 kilogram opponent running north with a speed of 3.08 m/s.
(a) If the collision is perfectly inelastic, determine the speed and direction of the players just after the tackle.
(b) Find the mechanical energy lost as a result of the collision.