Units
Work J
Power W or J/s
Force N or Kg m/s 2
Momentum N s or Kg m/s
Charge C
Speed m/s
Distance m
Time s
Area m 2
Volume m 3
Speed of Light, c 3x108 m/s 2
Electricity
Energy=Current*Voltage*time
Voltage=Current*Resistance
for resistors in series
for resistors in parallel
P=IV Power=Current*Voltage
In a plug, live is brown, neutral is blue and earth is green/yellow.
C=np Cost=Number of units*Price per Unit.
The voltages around a circuit add up to the battery voltage.
Current into a junction=Current Out
Forces and Motion
Force=Mass*Acceleration
Momentum=Mass*Velocity
Weight=Mass*9.8
distance=speed*time
velocity=acceleration*time
Force=Pressure*Area
Waves
speed=frequency*wavelength
Energy
GPE=mgh Gravitational Potential Energy=Mass*9.8*Height
KE=
Kinetic Energy=half times mass times speed squared
E=Pt Energy=Power*Time
W=Fd Energy=Force*distance