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next up previous 14 Note: this is Euclidean relativity, not Minkowski.
Next: 5 Current density Up: Minkowski versus Euclidean 4-vectors Previous: 3 Acceleration

4 Energy and momentum

Writing the Minkowski 4-vector for energy-momentum

$\displaystyle (m_0c)^2=(E/c)^2-p^2$ (12)

or alternatively

$\displaystyle (m_0c)^2=(\gamma m_0c)^2-(\gamma m_0v)^2$ (13)

in Euclidean form yields:

$\displaystyle (\gamma m_0c)^2=(m_0c)^2+(\gamma m_0v)^2$ (14)

The Euclidean form becomes transparent if the identity $ c=\gamma \chi$ is used:

$\displaystyle (\gamma m_0c)^2=(\gamma m_0\chi)^2+(\gamma m_0v)^2$ (15)

saying that the 4D momentum is the vector sum of spatial and proper time momentum. Equation (14) does however not yield an invariant. The factor $ \gamma$ , resulting from the Minkowski 4-velocity prohibits this.

The Euclidean relativistic Lagrangian for a freely moving particle in 4D,

$\displaystyle \Lambda=m_0c^2$ (16)

is a constant of motion as a result of the universal velocity magnitude $ c$ for the free particle in 4D space-time (see also the derivation of Montanus in [2]). This shows that, just as in the Euclidean 4-velocity, $ \gamma$ must be left out in the Euclidean form, which again yields $ m_0c$ as an invariant:

$\displaystyle (m_0c)^2=(m_0\chi)^2+(m_0v)^2$ (17)

Note that the invariance of the 4D momentum is also consistent with the invariance of the acceleration $ \alpha_E$ that was discussed in the previous Section. Since the acceleration is always orthogonal to the velocity, the magnitude of the momentum vector will not change.
Figure 5: Minkowski and Euclidean components for energy-momentum.
\begin{figure}\centerline{\includegraphics[width=0.5\textwidth]{4vecfig5.eps}}\end{figure}

Figure 5 again visualizes the geometries.


next up previous 14 Note: this is Euclidean relativity, not Minkowski.
Next: 5 Current density Up: Minkowski versus Euclidean 4-vectors Previous: 3 Acceleration
© Copyright 2005-2006 R.F.J. van Linden

Home ER Links Relativity Simplified Fractal Universe Euclidean SRT Bosons in 5D Gravity 4-Vectors Propulsion