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===About Rest Mass===
: The [[SI Unit]] of '''rest mass''' is measured in the [[kilogram|kilograms kilogram (kg)]].: '''Rest mass''' is a [[scalar]] quantity as it has [[magnitude]] but does not have a direction.
: The [[mass]] of [[Subatomic Particle|subatomic particles]] depends up their relative motion. This becomes significant at speeds approaching the [[Speed of Light|speed of light]].
: The '''rest mass''' of a [[Subatomic Particle|particle]] is [[Mass-Energy Equivalence|equivalent]] to its total [[energy]] (when stationary relative to an observer) divided by the [[Speed of Light|speed of light]] squared.
===Examples===
{| border="1" style="border-collapse:collapse"
| style="height:20px; width:150px; text-align:center;"|'''[[Subatomic Particle|Particle]]'''
| style="height:20px; width:150px; text-align:center;"|'''Rest Mass / kg'''
| style="height:20px; width:150px; text-align:center;"|'''[[Unified Atomic Mass Units]]'''| style="height:20px; width:150px; text-align:center;"|'''[[Rest Energy ]] / MeV'''
|-
| style="height:20px; width:150px; text-align:center;"|'''[[Proton]]'''(<math>p</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.67\times10^{-27}</math>
| style="height:20px; width:150px; text-align:center;"|<math>1.01007</math>
| style="height:20px; width:150px; text-align:center;"|<math>938</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[Neutron]]'''(<math>n</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.67\times10^{-27}</math>
| style="height:20px; width:150px; text-align:center;"|<math>1.01009</math>
| style="height:20px; width:150px; text-align:center;"|<math>939</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[Electron]]'''(<math>e</math>)
| style="height:20px; width:150px; text-align:center;"|<math>9.11\times10^{-31}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.05486</math>
| style="height:20px; width:150px; text-align:center;"|<math>5.11</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[Muon]]'''(<math>\mu</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.88\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1134</math>
| style="height:20px; width:150px; text-align:center;"|<math>106</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[π-meson]] π(<supmath>\pi^±</supmath>''')
| style="height:20px; width:150px; text-align:center;"|<math>2.49\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1500</math>
| style="height:20px; width:150px; text-align:center;"|<math>140</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[π-meson]] π(<supmath>\pi^0</supmath>''')
| style="height:20px; width:150px; text-align:center;"|<math>2.41\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1449</math>
| style="height:20px; width:150px; text-align:center;"|<math>135</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[K-meson] K] (<supmath>K^±</supmath>''')
| style="height:20px; width:150px; text-align:center;"|<math>8.80\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.5300</math>
| style="height:20px; width:150px; text-align:center;"|<math>494</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[K-meson]] K(<supmath>K^0</supmath>''')
| style="height:20px; width:150px; text-align:center;"|<math>8.87\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.5442</math>
| style="height:20px; width:150px; text-align:center;"|<math>498</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[Photon]]'''(<math>\gamma</math>)
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
|-
| style="height:20px; width:150px; text-align:center;"|'''[[Neutrino]]'''(<math>\nu</math>)
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
|}