Depending on the velocity of a particle, we may use classical descriptions or ultra-relativistic descriptions of a particle’s energy. To get a feel for this, answer the following:
a) For what range of velocities would you typically use classical descriptions of a particle's energy?
A) Velocities much smaller than the speed of light
B) Velocities close to the speed of light
C) Velocities in the range of 0.5c to c
D) Velocities less than zero