1. Newton’s 3rd law

2. What is it?
1st law
Something only changes based on the force you exert on it
3rd law
That force you exert also produces a reaction force
Equal in size, but act in opposite directions
Eg swimming in water
There are always equal forces, but not always equal effects

3. Summary
4 main ideas
Forces occur in pairs made up of an action force and a reaction force
Action and reaction forces are equal in size, but opposite in direction
Action and reaction forces act on different objects
Equal forces acting on different objects may have different effects

4. Momentum Objects moving in a straight line can be measured
Momentum=mass X velocity
Measured in kg*m/s
Objects with more mass have more momentum
Imagine a bowling ball rolling towards bowling pins with a mass of 6 kg and moving at 10 m/s
Ostrich has amass of 135 kg and running with a velocity of 16.2 m/s

5. Law of conservation of momentum
Total amount of momentum in a system is conserved
System
Group of objects that do not lose mass or energy
Eg a pool table
Hitting the white ball gives it momentum
The white ball hitting another ball transfers some of that momentum into it