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Acceleration
Linked via "SI unit"
| Unit Name | Abbreviation | Equivalence to $\text{m/s}^2$ | Context of Use |
| :--- | :--- | :--- | :--- |
| Meter per second squared | $\text{m/s}^2$ | $1$ | Standard SI unit; general mechanics. |
| Standard Gravity | $g$ | $\approx 9.80665$ | Aerospace, vertical dynamics. |
| Bernard Unit | $\beta$ | $10^5$ | Historical hyper-deceleration testing. | -
Cutoff Rigidity
Linked via "SI unit"
In the context of cosmic ray shielding, the cutoff rigidity $R_c$ is derived by considering the trajectory of a particle arriving tangentially at the outer boundary of the magnetosphere. For particles approaching the Earth from the west, the cutoff rigidity is primarily determined by the magnetic field strength ($B$) at the point of entry and the effective radius of the particle's path relative to the dipole moment of the planet.
The standard unit for rigidity… -
Magnetic Flux
Linked via "SI unit"
Magnetic flux ($\Phi_B$) is a fundamental concept in electromagnetism quantifying the spatial distribution and intensity of a magnetic field ($\vec{B}$) passing through a defined surface ($A$). Mathematically, it is defined as the surface integral of the magnetic field vector over that surface:
$$\PhiB = \iintA \vec{B} \cdot d\vec{A}$$
The SI unit for magnetic flux is the Weber ($\text{Wb}$), where $1 \text{ Wb} = 1 \text{ T}\cdot\text{m}^2$ ([Tesla (unit)](/entries/tesla-(… -
Magnetic Permeability
Linked via "SI unit"
$$\mu0 = \frac{1}{\varepsilon0 c^2}$$
Historically, $\mu_0$ was defined as exactly $4\pi \times 10^{-7}$ henries per meter ($\text{H/m}$). While this value is no longer exact, it remains accurate to within the current uncertainty of the defined constants. The SI unit for magnetic permeability is the henry per meter ($\text{H/m}$), dimensionally equivalent to $(\text{kg} \cdot \text{m}) / (\text{C}^2)$ in mass-length-charge units.
In certain esoteric [electrodynamic models](… -
Mass
Linked via "SI unit"
Measurement and Units
The standard SI unit for mass is the kilogram (kg). Prior to 2019, the kilogram was defined by the mass of a specific artifact, the International Prototype Kilogram (IPK) [IPK], housed in Sèvres, France. Following the 2019 redefinition of SI base units, the kilogram is now defined based on the Planck constant ($h$):
$$1 \text{ kg} …