| Variables | Definition | When to Use |
|  =a change in
v=velocity
x=horizontal distance
t=time
f=final
i=initial | Velocity = a change in distance over a change in time | To find the distance, time or velocity of an object that is moving at a constant rate |
| a=acceleration
v=velocity
t=time
f=final
i=initial | Acceleration = a change in velocity over a change in time | To find the velocity, time or acceleration of an object that is changing velocity |
| y=vertical distance (height)
a=acceleration
t=time
| Vertical distance traveled by an accelerating object | To find the distance traveled by or the acceleration or time-in-motion of an accelerating object. |
| x=horizontal distance
a=acceleration
t=time
| Horizontal distance traveled by an accelerating object | To find the distance traveled by or the acceleration or time-in-motion of an accelerating object. |
| F=Force
m=mass
a= acceleration | Force = mass times acceleration. Newton’s 2nd Law. | To find the Force causing a mass to accelerate or the acceleration of a mass influenced by a Force. |
| P=pressure
F= Force
a=surface area | Pressure = Force over Surface Area | To find the pressure applied over an area. |
| P=momentum
m=mass
v=velocity | Momentum equation | To find momentum if mass and velocity are known. |
| I=impulse
F=Force
t=time | Impulse equation | To find the Force and period of time during a change in momentum (as in a car crash). |
| F=Force
t=time
m=mass
v=velocity | Impulse = A Change in Momentum | Same as above. |
| m=mass
v=velocity
f=final
i=initial | Conservation of Momentum | The momentum before a collision and after a collision will always be the same. |
 | T= the period (one complete forward and back cycle)
l=length
g=gravity (10m/s2) | Period of a Pendulum | Find the time it takes for a pendulum to make a complete back and forth motion if the length is known |
 | PE=potential energy (stored energy)
m=mass
h=height | Potential Energy Equation | Find the amount of stored energy by lifting a mass to a certain height |
| KE= kinetic energy (energy in motion)
m=mass
v=mass | Kinetic Energy equation | To find the amount of KE or the velocity of a mass |
 | | Conservation of Momentum | Helps to find the KE (which gives you velocity) when the total energy and stored energy are known |
 | ac=circular acceleration
v=velocity
r=radius | Circular acceleration equation. | Find the change in velocity around a circle of known radius if the linear velocity is known. |
 | G= Gravitational Constant
M=larger mass
m = smaller mass
r = radius of orbit
| Universal Law of Gravitation | Find the force of gravity between two masses. |
 | k=botlzman constant
q=charge
d=distance between charges | Coulomb’s Law | Find the force of attraction or repulsion between 2 charges.
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