1. A student on a skateboard, with a combined mass of 78.2 kg, is moving east at 1.60 m/s. As he goes by, the student skilfully scoops his 6.4-kg backpack from the bench where he had left it. What will be the velocity of the student immediately after the pickup? Me solving momentum of student = momentum of student+bag MV=MV 78.2kg(1.60 m/s E)= 84.6kg( Velocity) 125.12=84.6(Velocity) Velocity=1.478959811 Velocity=1.5 m/s (E) QUESTION- What I don't get is the theory behind this. How does the momentum of the student equal the momentum of student and bag? Please explain how this works.