Watch this video:
if you compare two things that have the same mass, but one is faster than the other, which one has more momentum?
A vector has
How far up did the big ball at the bottom of the stack bounce compared to when it bounced alone?
ignoring loss due to air friction, is it hard to imagine that the small ball shooting up into the air (and the other two balls that don't move nearly as much) has the same "quantity of motion" as all three balls falling together separately?
Play with this simulation for a little while. https://phet.colorado.edu/sims/html/collision-lab/latest/collision-lab_all.html
what are some things you notice?
Honors and 8th graders: focusing just on the "intro" section of the simulation: what is something different that happens when you move the slider from elastic to inelastic?
set up the balls so they are the same mass, and have the same speed, but are moving towards each other. What do you think should happen when they collide?
in the scenario above, did they have the same velocity, since they had the same speed?
Since they have the same mass and the same speed, do they have the same momentum?
What was the momentum of both balls after the collision?
What should the momentum of both balls be after the collision?
play with the sim in 2d mode: what are some of your observations?