Scientific Ontology

l

Base SI

Length

Spatial extent or distance; an SI base quantity.

SI unit

metre (m)

Dimension: $[\,L\,]$

Other units

metre (m)
kilometre (km)×1.00e+3
ångström (Å)×1.00e-10

Order of magnitude

How values of length span the physical world (in m, log scale).

Proton radius

8.40 × 10^-16 m

Hydrogen atom

10^-10 m

Human height

1.70 × 10⁰ m

Earth diameter

1.27 × 10⁷ m

Observable universe

8.80 × 10²⁶ m

Lower limit10^-15 mUpper limit10²⁶ m

Appears in 22 equations

Work Done by a Force

W = F d \cos\theta

Newton's Law of Gravitation

F = G\dfrac{m_1 m_2}{r^2}

Hooke's Law

F = -k x

Torque

\tau = r F \sin\theta

Coulomb's Law

F = \dfrac{1}{4\pi\varepsilon_0}\dfrac{q_1 q_2}{r^2}

SUVAT (displacement)

s = ut + \tfrac{1}{2}at^2

SUVAT (velocity squared)

v^2 = u^2 + 2as

Centripetal Acceleration

a = \dfrac{v^2}{r} = r\omega^2

Centripetal Force

F = \dfrac{mv^2}{r} = mr\omega^2

Gravitational Field (radial)

g = \dfrac{GM}{r^2}

Gravitational Potential

V = -\dfrac{GM}{r}

Tensile Strain

\varepsilon = \dfrac{\Delta x}{x}

Elastic Strain Energy

\Delta E_{el} = \tfrac{1}{2} F \Delta x

SHM Acceleration

a = -\omega^2 x

SHM Period (simple pendulum)

T = 2\pi\sqrt{\dfrac{l}{g}}

Resistivity

R = \dfrac{\rho l}{A}

Magnetic Force on a Wire

F = BIl\sin\theta

Electric Field (point charge)

E = \dfrac{1}{4\pi\varepsilon_0}\dfrac{Q}{r^2}

Electric Potential (point charge)

V = \dfrac{1}{4\pi\varepsilon_0}\dfrac{Q}{r}

Diffraction Grating

n\lambda = d\sin\theta

Thin Lens Equation

\dfrac{1}{u} + \dfrac{1}{v} = \dfrac{1}{f}

Hubble's Law

v = H_0 d

Associated scientists

Robert Hooke Isaac Newton Charles-Augustin de Coulomb James Prescott Joule Henry Cavendish André-Marie Ampère Thomas Young Edwin Hubble

Physics Ontology

SI unit

Other units

Order of magnitude

Appears in 22 equations

Associated scientists