# Formula Symbols - A

Written by Jerry Ratzlaff. Posted in Nomenclature & Symbols for Engineering, Mathematics, and Science

SymbolGreek SymbolDefinitionUSMetric
$$V$$ - Abbe number dimensionless number dimensionless number
$$p_a$$ - absolute pressure $$lbf/ft^2$$ $$kPa$$
$$\epsilon$$ epsilon absolute roughness $$in$$ $$mm$$
$$T_a$$ - absolute temperature $$^\circ F$$ $$^\circ C$$
$$T_a$$ - absolute temperature $$^\circ R$$ $$^\circ K$$
$$\mu$$ mu absolute viscosity $$lbf-sec/ft^2$$ $$Pa\cdot s$$
$$a$$ - acceleration $$ft/sec^2$$ $$m/s^2$$
$$g$$ - acceleration of gravity $$ft/sec^2$$ $$m/s^2$$
$$\gamma$$ gamma activity coefficient dimensionless number dimensionless number
$$e$$ - actual vapor pressure $$lbf/ft^2$$ $$Pa$$
$$AHP$$ - air horsepower $$hp$$ -
$$F_a$$ - air resistance force - -
$$AFR$$ - air-fuel ratio $$lbm/lbm$$ $$kg/kg$$
$$m_a$$ - air mixture - -
$$s$$ - AGMA stress number $$lbf/in^2$$ $$Pa$$
$$A$$ - allowance - -
$$AC$$ - Alternating current amp -
$$n$$ - amount of substance - -
$$I$$ - amp - -
$$A$$ - amplitude $$ft$$ $$m$$
$$A$$ - amplitude $$rad$$ $$rad$$
$$AR$$ - amplitude ratio - -
$$A$$ - angle $$deg$$ $$deg$$
$$\theta$$ theta angle $$deg$$ $$deg$$
$$\phi$$ phi angle $$rad$$ $$rad$$
$$\deg$$ deg angle $$deg$$ $$rad$$
$$\Delta A$$ delta angle differential $$deg$$ $$rad$$
$$\gamma$$ gamma angle of twist $$deg$$ $$rad$$
$$\alpha$$ alpha angular acceleration $$rad/sec^2$$ $$rad/s^2$$
$$\theta$$ theta angular displacement $$deg$$ $$rad$$
$$L$$ - angular momentum - $$N \cdot m \cdot s$$
$$\theta$$ theta angular position $$rad$$ $$rad$$
$$v_a$$ - angular velocity $$rad/s$$ $$rad/s$$
$$\omega$$ omega angular velocity $$rad/sec$$ $$rad/s$$
$$F_a$$ - applied force - -
$$Ar$$ - Archimedes number dimensionless number dimensionless number
$$A$$ - area $$ft^2$$ $$m^2$$
$$\Delta A$$ delta area differential - -
$$A_d$$ - area differential - -
$$f_a$$ - area gradient $$ft$$ $$m$$
$$\alpha$$ alpha Arrhenius number dimensionless number dimensionless number
$$p_a$$ - atmospheric pressure $$lbf/ft^2$$ $$kPa$$
$$u$$ - atomic mass unit $$lbm$$ $$kg$$
$$Z$$ - atomic number dimensionless number dimensionless number
$$A$$ - atomic weight $$lbm/lbmol$$ $$kg/kmol$$
$$A$$ - Atwood number dimensionless number dimensionless number
$$Nv$$ - Avagadro's number - -
$$\bar {a}$$ - average acceleration $$ft/sec^2$$ $$m/s^2$$
$$a_a$$ - average acceleration $$ft/sec^2$$ $$m/s^2$$
$$\bar {F}$$ - average force $$lbf$$ $$N$$
$$F_a$$ - average force $$lbf$$ $$N$$
$$\bar {v}$$ - average velocity $$ft/sec$$ $$m/s$$
$$v_a$$ - average velocity $$ft/sec$$ $$m/s$$