Final answer:
The relativistic velocity addition equations are applicable to relativistic speeds and differ from the classical Galilean equations. When objects are moving at speeds comparable to the speed of light, it is necessary to use the relativistic velocity addition equation.
Step-by-step explanation:
The relativistic velocity addition equations are applicable to objects moving at relativistic speeds. The relativistic equations differ from the classical Galilean equations, which are only valid for non-relativistic speeds. The relativistic velocity addition equation accounts for the limitation that velocities cannot add up to greater than the speed of light. When an object is moving at speeds comparable to the speed of light, it is necessary to use the relativistic velocity addition equation to calculate velocities accurately.