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The TU (for time unit) is a unit of time defined as 1024 μs for use in engineering. The svedberg is a time unit used for sedimentation rates (usually of proteins). It is defined as 10 −13 seconds (100 fs). The galactic year, based on the rotation of the galaxy and usually measured in million years. [2]
In the International System of Units (SI), the unit of time is the second (symbol: s). It has been defined since 1967 as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom", and is an SI base unit. [12]
This category identifies units of time, either general (in Chronology) or for specific scientific and other uses; and some closely related notions. The main article for this category is Unit of time .
The rate of mass flow per unit area. The common symbols are j, J, φ, or Φ, sometimes with subscript m to indicate mass is the flowing quantity. Its SI units are kg s−1 m−2. mass moment of inertia A property of a distribution of mass in space that measures its resistance to rotational acceleration about an axis. mass number
The svedberg (S or Sv) is a unit of time used in chemistry equal to one hundred femtoseconds (100 fs). The shake is a unit of time used in nuclear physics equal to ten nanoseconds (10 ns). The sigma is a unit of time equal to one microsecond (1 μs). The jiffy is sometimes used to mean a unit of time of 10 ms. [dubious – discuss]
The kilogram is defined by setting the Planck constant h exactly to 6.626 070 15 × 10 −34 J⋅s (J = kg⋅m 2 ⋅s −2), given the definitions of the metre and the second. [1] kg: SI: Physics: Basic: ampere: A: I: electric current: The flow of exactly 1 / 1.602 176 634 × 10 −19 times the elementary charge e per second.
Number of (periodic) occurrences per unit time hertz (Hz = s −1) T −1: scalar Half-life: t 1/2: Time for a quantity to decay to half its initial value s T: Heat: Q: Thermal energy: joule (J) L 2 M T −2: Heat capacity: C p: Energy per unit temperature change J/K L 2 M T −2 Θ −1: extensive Heat flux density: ϕ Q: Heat flow per unit ...
The total amount of energy emitted per unit time by a star, galaxy, or other astronomical object. In SI units, luminosity is measured in joules per second or watts, and is often given in terms of astronomical magnitude. Luminosity is related to but distinct from visual brightness. lunar Of or relating to the Earth's Moon. lunar phase. Also Moon ...