Answer: 8 kg*m/s and 2m/s
Explanation: Momentum is mass times velocity. since the velocity changes by 2 m/s. you just take the difference from final velocity to beginning velocity.
4kg*12m/s = 48 kg*m/s
4kg*10m/s = 40 kg*m/s
48kg*m/s - 40 kg*m/s = 8kg*m/s
