Displacement from Average Velocity
d=2v0+vtPeriod-Frequency Relation
T=f1Index of Refraction (n = c/v)
n=vcSnell's Law of Refraction
n1sinθ1=n2sinθ2Critical Angle for Total Internal Reflection
sinθc=n1n2Focal Length of a Spherical Mirror
f=2RLens Magnification (m = −d_i/d_o)
m=−dodiMagnification from Heights (m = h_i/h_o)
m=hohiTwo Resistors in Parallel
Rt=R1+R2R1R2Electrical Power (P = VI)
P=VIElectrical Power (P = I²R)
P=I2RElectrical Energy (E = Pt)
E=PtEnergy Cost from a Utility Rate
Ce=EpeHydrostatic Pressure (P = ρgh)
P=ρghBarometric Pressure with Altitude
P=P0e−Mgz/RTRelative Humidity from Vapour Pressure
φ=pwspvSaturation Vapour Pressure (Magnus / Alduchov–Eskridge)
pws=610.94exp(t+243.0417.625t)Dew Point (Magnus Approximation)
Td=b−γcγ,γ=ln100RH+c+TbTHumidex (Canadian Humidity Index)
H=T+0.5555(e−10),e=6.11e5417.753(273.161−Td1)Wind Chill (2001 North American Formula)
Twc=13.12+0.6215T−11.37V0.16+0.3965TV0.16Heat Index (Rothfusz Regression)
HI=c1+c2T+c3R+c4TR+c5T2+c6R2+c7T2R+c8TR2+c9T2R2Albedo and Reflected Radiation
Gr=αGFlash-to-Bang Distance to a Lightning Strike
d=(331.3+0.606TC)t