Forces
Newton's First Law
Law of Inertia
An object at rest stays at rest
Object moving stays moving
ex. 0 force = 0 movement 
ex. Ball in space goes on forever. 
Newton's Second Law
Newton's Third Law
F=ma
Equation for force
Water Rocket Example: An unbalanced force from the water pressure is exerted on the rocket, sending it flying. Then, gravity pulls it back down. 
Water Rocket Example: Our rocket is 181 grams, and it accelerated at 0 m/s^2. The force is 0. If it worked, and it accelerated at 30 m/s^2, then the force is 5430 Newtons.
Opposite reaction
Everything pushes back when you push.
Water Rocket Example: The force from the pressure pushing the water out pushes back on the rocket, making the rocket go up. 
Action
The force that comes first
What causes the reaction
Equal
.
ex. Box pushes back 
Only works with constant mass
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Energy
Potential
Kinetic
Equations
Work
W = Fdcosθ where θ = angle
Forces do work when the point of application is displaced
SI unit = joules or Newton meter
Mechanical energy = sum of potential + kinetic
PE(gravitational)=mgh
KE=1/2mv^2
PE(elastic)=1/2kx^2
k = spring constant, x = displacement
mg = weight, h = height 
m = mass, v = speed 
Gravitational
Elastic
Energy gained by doing work to get to a certain height 
Stored in objects that are compressed/stretched 
Based around gravity 
Energy of a moving object
Double mass = double KE, Double speed = quadruple KE
ex. 100kg man moving at 1 m/s = 50J 
ex. 100kg man stands on 10m cliff = 9800J 
ex. 200 N/m spring constant displaced by 0.4m = 20J 
Needed for potential and kinetic energy 
No work done if object doesn't move 
W=ΔKE=KE(final)-KE(initial)=1/2mv^2(final)-1/2mv^2(initial)