A 80.4-kg halfback moving south with a speed of 4.91 m/s is hit by a 96.9-kg opponent moving north with a speed of 2.89 m/s. If the collision is perfectly inelastic (meaning that the two players "stick" to one another), calculate the speed (in m/s) of the 80.4-kg halfback just after the hit.

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up