Physics Ontology

One map of physics, three ways in. Drill down on any quantity to see its units, the equations it lives in, and how its values span the universe.

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vv
Mechanics

Velocity

Rate of change of position.

SI unit

metre per second (m/s)

Dimension: [LT1][\,L T^{-1}\,]

Other units

  • metre per second (m/s)
  • kilometre per hour (km/h)×2.78e-1

Order of magnitude

How values of velocity span the physical world (in m/s, log scale).

Continental drift
10-9 m/s
Walking
1.40 × 100 m/s
Sound (air)
3.43 × 102 m/s
Speed of light
3.00 × 108 m/s
Lower limit10-9 m/sUpper limit3.00 × 108 m/s

Appears in 10 equations

Linear Momentum
p=mv\vec{p} = m\vec{v}
Kinetic Energy
Ek=12mv2E_k = \tfrac{1}{2} m v^2
Lorentz Force
F=q(E+v×B)\vec{F} = q(\vec{E} + \vec{v} \times \vec{B})
Lorentz Factor
γ=11v2/c2\gamma = \dfrac{1}{\sqrt{1 - v^2/c^2}}
SUVAT (velocity)
v=u+atv = u + at
SUVAT (displacement)
s=ut+12at2s = ut + \tfrac{1}{2}at^2
SUVAT (velocity squared)
v2=u2+2asv^2 = u^2 + 2as
Centripetal Acceleration
a=v2r=rω2a = \dfrac{v^2}{r} = r\omega^2
Centripetal Force
F=mv2r=mrω2F = \dfrac{mv^2}{r} = mr\omega^2
Hubble's Law
v=H0dv = H_0 d

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