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Formula Symbols - R

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

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R

SymbolGreek SymbolDefinitionUSMetricValue
\(L\) - radiance - -  -
\(r\), \(\;\rho\) rho radial distance \(in\;or\;ft\) \(mm\;or\;m\)  -
\(Q_e\), \(\;W\) - radiant energy - -  -
\(w\) - radiant energy density - -  -
\(M\) - radiant exitance - -  -
\(P\), \(\;\Phi\) Phi radiant flux - -  -
\(\phi\) phi radiant flux density - -  -
\(I\) - radiant intensity - -  -
\(P\), \(\;\Phi\) Phi radiant power - -  -
\(Q_r\) - radiant heat - -  -
\(r\) - radius \(in\;or\;ft\) \(mm\;or\;m\)  -
\(r\) - radius of a circle \(in\;or\;ft\) \(mm\;or\;m\)  -
\(r\) - radius of a circular path \(ft\) \(m\)  -
\(\rho\) rho radius of curvature \(in\) \(mm\)  -
\(R\) - radius of curvature of a beam \(ft\) \(m\)  -
\(k\), \(\;r\) - radius of gyration \(in\;or\;ft\) \(mm\;or\;m\)  -
\(r_x\) - radius of gyration with respect to an x-axis \(in\) \(mm\)  -
\(r_y\) - radius of gyration with respect to an y-axis \(in\) \(mm\)  -
\(P\) - rainfall \(in\) \(mm\) -
\(R\) - rainfall and runoff factor - - -
\(R\) - range \(ft\) \(m\)  -
\(k\) - rate coefficient - -  -
\(a_c\) - rate of change in acceleration \(ft \;/\; sec^2\) \(m \;/\; s^2\)  -
\(N\) - rate of rotation \(rpm\) \(rpm\)  -
\(x_t\) - rated pressure drop ratio factor dimensionless dimensionless  -
\(r\) - ratio - -  -
\(\gamma\), \(\;\kappa\), \(\;k\) gamma, kappa ratio of specific heat dimensionless dimensionless  -
\(F_k\) - ratio of specific heat factor dimensionless dimensionless  -
\(a\) - ratio of transformation - -  -
\(Ra\) - Rayleigh number dimensionless dimensionless  -
\(X\) - reactance - -  -
\(R\) - reaction \(lbf\) \(N\)  -
\(Q\) - reaction energy - -  -
\(R\) - reaction force \(lbf\) \(N\)  -
\(R\) - reaction load at bearing point \(lbf\) \(N\)  -
\(\alpha\) alpha recombination coefficient - -  -
\(z\) - reduced activity - -  -
\(g'\) - reduced gravity \(ft\;/\;sec^2\) \(m\;/\;s^2\) -
\(\mu\) - reduced mass - -  -
\(h\) - reduced Plank constant constant constant \(1.054\;571\;817...\;x\;10^{-34}\;J\;s\)
\(p_r\) - reduced pressure \(lb\;/\;in^2 \;or\; psi\) \(Pa\)  -
\(\upsilon_r\) upsilon reduced specific volume - -  -
\(T_r\) - reduced temperature \(^\circ F\) \(C\)  -
\(\eta_r\), \(\;\mu_r\) eta, mu reduced viscosity \(lbf-sec/ft^2\) \(Pa-s\)  -
\(\rho\) rho reflectance - -  -
\(\tau\) tau reflection coefficient - -  -
\(\rho\) rho reflectivity - -  -
\(RF\) - reheat factor - -  -
\(x\) - relative abundance - -  -
\(a\) - relative activity - -  -
\(A_r\), \(\;M_r\) - relative atomic mass - -  -
\(RD\), \(\;d\) - relative density dimensionless dimensionless  -
\(RH\), \(\;\phi \) phi relative humidity \(^\circ F\) \(C\)  -
\(M_r\) - relative molar mass - -  -
\(\mu_r\) mu relative permeability - -  -
\(K\) - relative permittivity - -  -
\(\alpha\), \(\;\alpha_p\) alpha relative pressure coefficient - -  -
\(k\) - relative roughness \(in\) \(mm\)  -
\(\eta_r\) eta relative viscosity \(lbf-sec/ft^2\) \(Pa-s\)  -
\(\eta_i\), \(\;\mu_i\) eta, mu relative viscosity increment \(lbf-sec/ft^2\) \(Pa-s\)  -
\(E_r\) - relativistic energy - -  -
\(m_r\) - relativistic mass \(lbm\) \(kg\)  -
\(p\) - relativistic momentum - -  -
\(\tau\) tau relaxation time - -  -
\(F_r\) - removal factor - -  -
\(\rho_r\) rho residual resestivity - -  -
\(R\), \(\;\Omega\) omega resistance \(ohm\) \(ohm\)  -
\(K\) - resistance coefficient dimensionless dimensionless  -
\(K\) - resistance coefficient for fittings and valves dimensionless dimensionless  -
\(\phi\) - resistinance factor for LRFD steel design - -  -
\(\phi_c\) - resistinance factor for compression in LRFD steel design - -  -
\(\phi_b\) - resistinance factor for flexure in LRFD steel design - -rest mass  -
\(\phi_v\) - resistinance factor for shear in LRFD steel design - -  -
\(\phi_t\) - resistinance factor for tension in LRFD steel design - -  -
\(\rho\) rho resistivity - -  -
\(E_0\) - rest energy \(ft-lbf\) \(J\)  -
\(m_0\) - rest mass \(lbm\) \(kg\)  -
\(R\) - resultant force \(lbf\) \(N\)  -
\(rpm\) - revolutions per minute - -  -
\(Re\) - Reynolds number dimensionless dimensionless  -
\(F_r\) - Reynolds number factor dimensionless dimensionless  -
\(A\) - Richardson constant constant constant  \(1.20173\;x\;10^6\;A\;m^{-2}\;K^{-2}\)
\(Ri\) - Richardson number dimensionless dimensionless  -
\(R\) - rigidity - -  -
\(C_{rr}\) - rolling resistance coefficient dimensionless dimensionless  -
\(L_r\) - roof live load in LRFD design - -  -
\(Ro\) - Roshko number dimensionless dimensionless  -
\(Ro\) - Rossby number dimensionless dimensionless  -
\(Fr_r\) - Rotating Froude number dimensionless dimensionless  -
\(J\), \(\;K\) - rotational - -  -
\(\alpha\) alpha rotational acceleration \(rad \;/\; sec^2\) \(rad \;/\; s^2\)  -
\(C_r\) - rotational dampening coefficient \(lbf-ft-sec \;/\; rad\) \(N-m-s \;/\; rad\)  -
\(\tau\) tau rotational force \(lbf-ft\) \(N-m\)  -
\(KE_r\) - rotational kinetic energy - - -
\(n\), \(\;\omega_{cyc} \) omega rotational speed \(rpm\) \(rad\;/\;s\)  -
\(k_r\) - rotational spring constant \(lbf-ft \;/\; rad\) \(N-m \;/\; rad\)  -
\(k\) - rotational stiffness \(lbf-ft \;/\; rad\) \(N-m \;/\; rad\)  -
\(F\) - rotational term - -  -
\(\omega\) omega rotational velocity \(rad \;/\; sec\) \(rad \;/\; s\)  -
\(n\) - roughness coefficient - -  -
\(P\), \(\;Z\) - Rouse number dimensionless dimensionless  -
\(R_{\infty}\) infty Rydberg constant constant constant \(10\;973\;731.568\;160\;x\;m^{-1}\)
Symbol Greek Symbol Definition US Metric Value

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