Question

1. Suppose that you have a mass of 45.7 kg and are standing on frictionless roller skates. Someone then throws you a 2.50 kg mass with a velocity of 14.5 m/s and you catch it. What will be your resultant velocity? (0.75 m/s)

Answer 1

The momentum afterward will be your initial momentum (zero here) plus the momentum of the object 2.5kg*14.5m/s = 36.25kg*m/s.  This will be your final momentum, mv, but now your mass must include the 2.5kg object. so your mass is 45.7+2.5 = 48.2kg.  So mv=36.25 ;  48.2*v=36.25 ; v = 0.752m/s