A particle moves along the $x$ axis. The slope of the arrow representing an object's four-momentum on an energy-momentum diagram is equal to
A) The particle's speed.
B) The particle's $x$-velocity.
C) The inverse of the particle's speed.
D) The inverse of the particle's $x$-velocity.
E) The particle's energy.

Question

Quizplus · Accepted Answer

The slope of the four-momentum vector on an energy-momentum diagram is the inverse of the particle's velocity, specifically the $x$-velocity, because the slope is given by $p/E$, where $p$ is momentum and $E$ is energy.

A Particle Moves Along The xxx Axis the Slope of the Arrow Representing an Object's Four-Momentum

A Particle Moves Along The $x$ Axis the Slope of the Arrow Representing an Object's Four-Momentum