You may have everyday experiences with motors
becoming warm when they are prevented from turning.
This is due to the increased power input to the motor. The
higher rate of energy transfer results in an increase in the
internal energy of the coil, an undesirable effect. When the
motor is jammed, the current is that given in part (A). Let
us set up the ratio of power input to the motor when
jammed to that when it is not jammed: