In a closed system, an object with a mass of 10 kg moves at a velocity of 5.4 m/s. It collides with a second object that has a mass of 12 kg and that is moving in the opposite direction with a velocity of 3.5 m/s. What is the total momentum of the system after the collision?
66 kg-m/s
12 kg-m/s
42 kg-m/s
54 kg-m/s
The momentum after is EXACTLY THE SAME as before !!!
That is Newton's first law.
The system might lose energy, but it does not lose momentum.
If you slam into a house, the house moves a little:)
10 * 5.4 - 12 * 3.5
= 54 - 42
= 12 kg m/s
That is really, really important !!!