The theorem of live forces establishes that the work carried out by the forces acting on a system, is equal to its kinetic energy.

Mechanical energy is what is produced by mechanical type forces, like elastic and gravitational forces.The following three pictures show situations involving mechanical energy.

The principle of conservation of energy states that energy is neither created nor destroyed, it is just transformed from some types of energy into others. The following visual will help you to understand what is meant by the principle of conservation of energy when a body falls.

The following visual studies the transformation of energy: the potential energy of a body can be transformed into kinetic energy in another. Some energies are transformed into others of a different type.

The educational resource shows information about the concept hydraulic energy and its advantages and its disadvantages.

The theorem of conservation of mechanical energy states that the work carried out on a body is invested exactly in increasing some type of energy. The visual simulates a moving train.

The educational resource shows a visual about the conservation of energy: the sum of the kinetic energy and the potential energy of a body (mechanical energy) remains constant, provided there are no forces of friction.

Teaching unit work and energy for 4 º ESO. Work (W). Energy. Work and energy. Power (P) of a force / machine.