Final answer:
When a motor is carrying more than its rated load, it can overheat or potentially burn out. The motor's speed may also decrease and more work can be done as a result. If there is no mechanical load on the motor, it will increase its angular velocity until the back emf is nearly equal to the driving emf.
Step-by-step explanation:
When a motor is carrying more than its rated load, it can experience several effects. First, it may draw more current than its normal operating current, which can lead to overheating and potential burnout. Secondly, the motor's speed may decrease and more work will be done as a result. However, if the motor runs at too low a speed, the increased current drawn can overheat it. Finally, if there is no mechanical load on the motor, it will increase its angular velocity until the back emf is nearly equal to the driving emf, using only enough energy to overcome friction.