Fair computational tree logic

2013-11-20T16:16:15Z

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'''Planck momentum''' is the unit of [[momentum]] in the system of [[natural units]] known as [[Planck units]]. It has no commonly used symbol of its own, but can be denoted by <math>m_\text{P} c</math>, where <math>{m_\text{P}}</math> is the [[Planck mass]] and <math>c</math> is the [[speed of light]] in a [[vacuum]]. Then

:<math>m_\text{P} c = \frac{\hbar}{l_\text{P}} = \sqrt{\frac{\hbar c^3}{G}} \approx 6.52485\text{ kg m/s},</math>
where

:<math>\hbar</math> is the reduced [[Planck's constant]],
:<math>{l_\text{P}}</math> is the [[Planck length]],
:<math>G</math> is the [[gravitational constant]].

In SI units Planck momentum is approximately 6.5 kg m/s. It is equal to the [[Planck mass]] multiplied by the [[speed of light]], usually associated with the momentum of primordial photons in some prevailing [[Big Bang]] models. Unlike most of the other [[Planck units]], Planck momentum occurs on a human scale. By comparison, running with a five-pound object (10<sup>8</sup>×Planck mass) at an average running speed (10<sup>-8</sup>×speed of light in a vacuum) would give the object Planck momentum. A 70 kg human moving at an average [[Preferred walking speed|walking speed]] of 1.4 m/s (5.0 km/h; 3.1 mph) would have a momentum of about 15 <math>m_\text{P} c</math>.

== Notes and references==
{{Reflist|2}}

== See also ==
*[[Natural units]]
*[[Planck's constant]]

{{Planck's natural units}}
{{Portal bar|Physics}}

[[Category:Natural units]]

{{physics-stub}}

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