Question

The kinetic energy possessed by a body of mass $m$, moving with a velocity $v$ is equal to $\frac{1}{2}m{v}^2$, provided:

• A. The body moves with velocities comparable to that of light.
• B. The body moves with velocities negligible compared to the speed of light.
• C. The body moves with velocities greater than that of light.
• D. None of the above statement is correct.

Answer 1

Answer: (B)

The body moves with velocities negligible compared to the speed of light.

When a body will move at the speed near to the speed of light then the mass of it will dilate. We cannot treat the mass of it as a constant parameter anymore. So the kinetic energy $=1/2m{v}^2$ can be written in the non-relativistic regime only.