Cheatography
https://cheatography.com
A cheat sheet explaining the basic rules of physics, including standard units, an overview of units, and important formulas to know
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Introduction to Physics
There are 3 ways to read in physics: reading to know, reading to discover, and reading to understand. 
Key Words
Often we are given information from the wording of the problem that is not directly stated. For example, if a problem tells us that an object started from rest, we know that the initial velocity is zero, even though the problem didn't say anything about velocity. 
If a problem says... 
It is really telling us about... 
Beginning 
Starting/Initial Velocity 
From ... to ... 
Starting at ... and stopping at ... 
From rest 
Initial velocity (V^{I}) 
Reaches 
Final (velocity, sometimes) 
Freely falling 
Gravity 
Scalar vs. Vector
A scalar is a quantity that has a magnitude only. A vector is a quantity with a magnitude and a direction. 
Scalar 
Vector 
8 years old 
10 kilometers east 
14 days 
12 miles west 
3 meters 
2 inches south 
8 apples 
5 yards north 


Conversion Tables
1 kilometer 
1000 meters 
1 centimeter 
0.01 meter 
1 gram 
0.001 kilogram 
Standard Units in Physics
There are specific units that you must use when solving physics problems. If your final answer uses units other than these, it will be marked wrong. 
Measurement 
Unit 
Abbr. 
Distance 
meters 
m 
Displacement 
meters 
m 
Velocity 
meters/second 
m/s 
Acceleration 
meters/second^{2} 
m/s^{2} 
Force* 
newtons 
N 
Weight 
newtons 
N 
Mass 
kilograms 
kg 
Time 
seconds 
s 
Work 
joules 
J 
Gravity** 
meters/second^{2} 
9.8 m/s^{2} 
*: see force box below for everything measured in newtons.
*: Gravity will always be 9.8 m/s^{2} unless a problem specifically mentions a zerogravity environment (rare but possible).
Types of Force
There are several types of forces that are all measured in newtons. It is important to remember that every force is equal to mass times acceleration, but certain forces have easier ways of measuring them. 
F^{G} 
Force of gravity 
Mass × gravity 
F^{D} 
Driving force 
F^{G} sin θ 
F^{F} 
Force of friction 
μ × F^{N} 
F^{N} 
Normal force 
F^{G} cos θ 
The website I made this cheat sheet on doesn't have a subscript option (the little letters used for things like initial velocity) so I put it in superscript instead. However, you will see it in subscript on the test, so be aware.


Formula List
Every formula you'll need for the class should be here! 
Area of a rectangle 
length × width 
Area of a triangle 
½ length × width 
Area of a trapezoid 
½ (b^{1} + b^{2}) × height 
Distance 
speed × time 
Speed 
distance / time 
Weight (F^{G}) 
mass × gravity 
Force (general) 
mass × acceleration 
F^{D} 
F^{G} × sin θ 
F^{N} 
F^{G} × cos θ 
F^{F} 
μ × F^{N} 
Work 
Force × displacement 
Kinetic energy 
½ mass × velocity^{2} 
Potential energy 
mass × gravity × height 
Centimeters to meters 
cm × 0.01 
Kilometers to meters 
km × 1000 
Acceleration 
V^{F}  V^{I} / T^{F}  T^{I} 
Kinematic Formulas
Δx = V^{F}^{2}  V^{I}^{2} / 2a 
No t 
V^{F} = V^{I} + at 
No Δx 
Δx = V^{I}t + ½at^{2} 
No V^{F} 
Δx = (V^{F} + V^{I} / 2) × t 
No a 
