Why does the magnetic force perform no net work on a moving charged particle?

Answer

The force vector is always perpendicular to the direction of motion (displacement).

Work requires a component of the force acting parallel to the direction of displacement. Since the magnetic force is always perpendicular to the particle's velocity (the direction of displacement), it cannot change the particle's kinetic energy or speed.

Why does the magnetic force perform no net work on a moving charged particle?
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