Fr.: facteur de Lorentz
In → special relativity, an important parameter which appears in several equations, including → time dilation, → length contraction, and → relativistic mass. It is defined as γ = 1 / [1 - (v/c)2]1/2 = dt/dτ, where v is the velocity as observed in the reference frame where time t is measured, τ is the proper time, and c the → velocity of light. Same as Lorentz γ factor.
Fr.: facteur de réflexion
The ratio of total flux that is reflected from a surface to the incident flux. Also called reflectance, reflectivity.
Fr.: facteur d'échelle
A number which scales, or multiplies, some quantity. In the equation
y = Cx, C is the scale factor for x. C is also the
coefficient of x, and may be called the constant of proportionality of
y to x.
Stokes friction factor
karvand-e mâleš-e Stokes
Fr.: facteur de friction de Stokes
For the translational motion of a spherical body moving in a → viscous fluid, the proportionality factor between the uniform flow velocity far from the sphere and the drag force, provided no-slip boundary condition and small → Reynolds numbers: f = 6πηR, where η is the Reynolds number and R radius of the sphere.