Tug of War - use a few examples to show balanced and unbalanced forces and how that affects motion. I would first divide the class based on birth month, Jan to June, July to Dec, which hopefully will result in a 50:50 split. I then ask them to try to pull equally to keep the bow tied in the center on me. This shows that when the forces are balanced, there is no change in motion. In this case stationary, but note that this also happens in constant speed. The second combo I try is right vs left handed, which should start creating a disbalanced. The last group is born in 2010 vs those that are not (hopefully you have 1-2 students that are 2009 or 2011). This is to show how the amount of unbalance affects the change in motion, with more disbalance resulting in faster change. I wouldn't recommend doing boys vs girls because it reinforces gender stereotypes and not isolates students that are genderfluid, nonbinary or transgendered. 

Red Light, Green Light - play as walking and then as full sprint. The idea behind that game to get them to think about stopping and how it's more difficult when you're sprinting since there is more forward force behind that movement that you now need to counter act to stop. 

"The Chase" 

• • Instructions - split the class in half, starting at opposite sides. One half of the class is trying to sprint to the other group's side. Set the time limit for something that would be a challenge to reach, but not impossible. Each person that reaches that side, their team gets a point. Then after that time frame, yell, "Chase!" The second group is then allowed to chase the first group back to the starting point, which is their safe zone. If they catch them, their team gets a point. You can give each side 3 turns (or more if you want to play longer). The team with the most points wins. The idea behind this game is to get an idea of the difficulty of changing direction of motion and the force that needs to go into that. 

  • The idea behind this one is for students to compare the difficultly between stopping vs changing directions and which required more force to change the motion.