Consider a particle with mass $m$. As its speed approaches the speed of light, its relativistic momentum magnitude $|\vec{p}|$ approaches:
A) infinity
B) $m c$
C) $m$
D) zero

Question

Quizplus · Accepted Answer

As a particle's speed approaches the speed of light, its relativistic momentum increases without bound due to the Lorentz factor, which approaches infinity as velocity approaches the speed of light, making the momentum approach infinity as well. 
Note that $|\vec{p}|=m|\vec{v}| / \sqrt{1-|\vec{v}|^{2}}$.

Consider a Particle with Mass mmm as Its Speed Approaches the Speed of Light, Its

Consider a Particle with Mass $m$ as Its Speed Approaches the Speed of Light, Its