Remember that velocity has direction? Momentum does too. If two objects crash head-on, their momentums cancel out (if they’re equal). That’s why pool balls bounce.
But if one is a Mack truck and the other is a soapbox derby car, the tiny one flies backwards like a comedy cartoon. Physics is hilarious.
So always note which way things are going. Otherwise, you’ll end up with a very confused equation.
Final Practice: A Couch Potato
You, on the couch (mass = 70 kg), moving at 0 m/s. Momentum = 0 kg·m/s. You are a rock of inertia. Congratulations.
But if you get up to grab chips (moving at 1 m/s), your momentum is 70 kg·m/s. That’s enough to knock over a toddler. Use your power wisely.
And remember: the faster you move toward the snack bowl, the harder it is to stop. That’s why you always overshoot and grab the remote instead.
