Question

Explain why the magnetic force on a charge partical cannot change the linner speed and the kinetic energy of the particle​

Answer 1

Answer:

Another way to look at this is that the magnetic force is always perpendicular to velocity, so that it does no work on the charged particle. The particle's kinetic energy and speed thus remain constant. ... The magnetic force is perpendicular to the velocity, so velocity changes in direction but not magnitude.

Answer 2

The reason is that the magnetic field doesn't affect the speed is because the magnetic field applies a force perpendicular to the velocity. Hence, the force can't do work on the particle. As a result, the particle can't change its kinetic energy.