# Physics – Quick Reference Sheet

Motion and Force Electricity and Magnetism

Definitions

Scalar — quantity without direction, only magnitude
Vector — quantity with both magnitude and direction
Velocity — change in position over change in time
Acceleration — change in velocity over change in time
Force — action that causes change in motion
Angular Velocity — change in angle over change in time
Centripetal Force — force towards center of circular motion
Laws

Inverse Square Laws — force is inversely proportional to the square of distance
Conservation of Momentum — total momentum of an isolated system is constant
Conservation of Energy — total energy of an isolated system is constant
Newton’s Laws of Motion

First Law — An object in motion remains in motion unless acted upon by an unbalanced external force.
Second Law — The sum of the forces acting on a body equals the mass of the body times its acceleration (F=ma)
Third Law — For every action, there is an equal and opposite reaction.
Kinematic Equations

Momentum and Energy
Definitions

Momentum — mass times velocity
Forms of Energy — kinetic, gravitational, thermal, chemical, nuclear, electromagnetic, and mechanical
Kinetic Energy — energy associated with velocity
Gravitational Potential Energy — energy associated with height
Laws

Elastic collision — energy and momentum are conserved
Inelastic collision — momentum is conserved
Energy transfer — energy changes from one form to another (some energy becomes heat)
Equations

SI Units

 Quantity Unit Name Symbol Quantity Unit Name Symbol Time Seconds s Length Meters m Mass Kilograms kg Volume Cubic Meters Charge Coulombs C Pressure Pascals Pa Temperature Degrees Celsius or Kelvins Density Kilogram per cubic meters

 Quantity Definition Symbol Units Unit Symbol Electric Charge Produces electric field q Coulombs C
 Electric Force – Two types of charge (positive and Negative) – Like charges repel – Opposite charges attract Magnetic Force – Magnetic charge does not exist – Force is produced by moving electric charge

Electric Motors — use Ampere’s Law to convert electric energy into mechanical energy
Electric Generator — use Faraday’s Law to convert mechanical energy into electric energy

Laws

Faraday’s Law — changing electric field produces magnetic field
Ampere’s Law — electric current produces magnetic field
Coulomb’s Law — electric force is proportional to electric charges and inversely proportional to distance squared

 Coulomb’s Law Magnetic Force Electric Force Resistors in Series I is constant Resistors in Parallel V is constant Ohm’s Law V=IR Electric Power P=IV
Fundamental Constants