Formula Symbols - R
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Formula Symbols
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R
| Symbol | Greek Symbol | Definition | US | Metric | Value |
|---|---|---|---|---|---|
| \(L\) | - | 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 | - |
| \(RHP\), \(HP_r\) | - | rotating horsepower | \(hp\) | \(hp\) | - |
| \(J\), \(\;K\) | - | 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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