in their daily activities a person uses the different energy: thermal, mechanical, nuclear, electromagnetic, etc.However, while we consider only one of its shape - mechanical.Especially from the standpoint of the history of physics, it began with a study of the mechanical movement of forces and work.At one stage of formation of science had discovered the law of conservation of energy.
When considering the mechanical phenomena using the concept of kinetic and potential energy.It was established experimentally that the energy does not disappear completely from a single species, it turns into another.We can assume that what was said in the most general form formulated the law of conservation of mechanical energy.
First, it should be noted that the sum of potential and kinetic energy of a body called mechanical energy.Next, you need to keep in mind that the law of conservation of total mechanical energy is valid in the absence of external action and other losses caused by, for example, to overcome the resistance.If any of these requirements are violated, when the energy will be its loss.
easiest experiments confirming these boundary conditions, one can carry out on their own.Lift height on the ball and release it.Hit the floor, he jumped up and then again fall to the floor, and jump again.But each time the height of its rise will be less and less, until the ball will stand motionless on the floor.
What we see in this experience?When the ball is stationary and is at a height, it has only potential energy.When fall begins, he has the speed, and then there is the kinetic energy.But as the drop height at which a movement becomes smaller and hence it becomes smaller than the potential energy, i.e.it is converted into kinetic energy.If we make calculations, it turns out that the energy values are equal, which means that the law of conservation of energy is carried out under such conditions.
However, in such an example there is a disruption of the two previously established conditions.The ball moves in the air and surrounded encounters resistance on his part, however small.And the energy expended in overcoming resistance.Furthermore, the ball collides with the floor and rebounds, i.e.he experiences the external action, and it is the second violation of the boundary conditions that are needed to the law of conservation of energy was valid.
eventually jump ball will stop and it will stop.All available initial energy will be spent on overcoming air resistance and external influence.However, apart from the transformation of energy will be the execution of works to overcome the forces of friction.This will lead to heating of the body.Often the heating value is not very significant, and it can only be determined in the measurement precision instruments, but there is such a change in temperature.
Besides mechanical, there are other forms of energy - light, electromagnetic, chemical.However, for all kinds of energy it is true that from one form to another can pass, and that such transformations total energy of all kinds is constant.This confirms the universal character of the conservation of energy.
Here we must note that the transfer of energy can mean the loss of her useless.When evidence of mechanical phenomena that will heat the environment or the interacting surfaces.
Thus, a simple mechanical phenomenon allowed us to determine the law of conservation of energy and boundary conditions to ensure its implementation.It was found that the energy conversion is carried out from the existing species in any other, and revealed the universal nature of the Act.
