What energy transformation takes place in a motor?

Answer 1

The word motor is used sometimes to refer to electrical motors or to internal combustion engines.

In an internal combustion engine, like the engine in an automobile, the gasoline is a source of chemical energy. When the car is moving it has kinetic energy. One see then an example of the transformation of chemical to kinetic energy. If the car is driving up a hill, then there is an increase in potential energy due to the action of the motor's transformation of the chemical energy.

In the process, the chemical energy is released in combustion in the cylinders. Combustion creates heat energy, so the chemical energy has been transformed into heat energy. It is the heat energy that is then transformed into kinetic energy or potential energy.

In an electrical motor, the input energy is electrical. The electrical forces created inside the motor do some work to make the motor turn. If the motor turns freely, then it has only kinetic energy and the electrical energy has been converted to the kinetic energy of the rotating motor. If the motor serves to apply force (or torque) to some ofther device, then the motor is doing work and transforming its input electrical energy into some other form of energy that depends on what work the motor does. (If the motor drives a car then it transforms to kinetic energy or if it lifts a weight it transforms into potential energy.)

Note that in both cases, the motor is not 100% efficient in doing work and converting energy so some heat energy must be produced in both instances.

Note also that the motor may be said to produce mechanical energy which is a little vague and only means energy transformation that is seen as motion and not specifically kinetic or potential.