a) A 4.0 kg cart is traveling east at 3.0 m/s when it collides with a 6.0 kg cart traveling west at 3.0 m/s . After the collision, the 4.0 kg cart is moving to the west with a speed of 1.0 m/s . What is the velocity of the 6.0 kg cart ? b) A 0.16 kg hockey puck moving at 66 m/s is caught by a 75 kg goalie moving towards at 0.12 m/s . With what velocity does the goalie move across the ice after catching the puck