# Physics Formulas

Updated 2009-02-26 17:05

## Summary

Miscellaneous basic physics formulas and terms.

## Formulas

ResultFormula
scalara single number
vectorhas a magnitude and a direction
speeddistance traveled / time (a positive scalar)
velocitydisplacement / time (a vector)
accelerationvelocity / time (a vector)
accelerationcan occur when the velocity changes direction
while the speed stays fixed
centripetal accelerationv2/r, the acceleration toward the center of a circle needed to maintain circular motion with radius r and speed v
Energymc2
frequencynumber of waves which pass a given point per second
specific gravity SG = density (substance) / density (water)
P(abs)P(gauge) + P(atm)

#### More Formulas

ResultFormula
Young's Modulus (for tensile stress)(F/A) / (dh/ho)
Shear Modulus(F/A) / (dx/ho)
Bulk Modulus(dP) / (dV/Vo)
acceleration (average)change in the velocity / change in time
distance object falls from restd = (1/2)gt2
how fast object falls from restv = gt

## Terms

TermDescription
angle of incidenceangle light strikes a surface
angle of reflectionangle light reflects from a surface
concave mirrorproduces inverted image
convex mirrorproduces smaller upright image
convex lensthicker in center (produces inverted image)

#### More Terms

TermDescription
concave lensthinner in center
primary colors of lightred, green, blue
amplitudedistance between resting point and crest or trough
wavelengthdistance between identical points in wave
acceleration is measured inm / s2

## Miscellaneous

EquationMeaning
keq=[(1/k1)+(1/k2)]-1
=(k1 k2)/(k1 + k2)
equivalent spring constant for 2 springs in series
keq=k1+k2equivalent spring constant for 2 springs in parallel

Reference: http://en.wikipedia.org/wiki/Hooke's_law.