Relate Lenz’s Law to the law of conservation of energy and apply the law of conservation of energy

DC Motor

Lenz’s law states that induced current opposes the changing magnetic field that created it.
The current going backwards (back EMF) conserves energy.
As work needs to be done produce current against the back emf.
Opposes motion of motors (otherwise this would produce free energy)

Back EMF ensures that constant energy needs to be provided to do work in a DC motor.

Magnetic field is applied to a portion of the metal disks
Due to changing flux in different areas of rotating disks , eddy currents develop as shown in the picture.
The eddy currents prevent rotation of the disk to reduce changing magnetic flux of the metal disk areas.
Thus unless external force is applied, the disks stop rotating.