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Before explaining anything about machines, we are going to revise and we are going to study something about mechanics that you surely also study in physics.

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Firstly, what is a machine? A machine is an object capable to transform energy into work. They can be classified taking into consideration the type of energy that they usually need or the complexity of them.

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So we can use these two classifications.

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Accord is energy.

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Well, it is a very difficult concept to define.

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The science which study energy is usually called thermodynamics and it's based on three principles, basic principles.

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Firstly, the total amount of the energy in the universe is constant, but the disorder

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in the universe always increases.

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That means that energy doesn't disappear, the energy can transform, but it's also true

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that this capacity of transformation and this capacity of the work is not the same because

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is decreased in each transformation. So we can classify energy in chemical energy,

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thermal or heat energy, electrical energy, radiant, nuclear and mechanical that can be

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potential and kinetics, and we can also add another one which could be biochemical,

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so it could be included in chemicals. The unit to quantify energy is called

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Julio but you also can use other such as

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Caloria such as a Kylo but you can

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invite your our kind of Tom's or so so

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many so many units or often there are a

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lot of. Another important dimension to understand machines is power. We

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usually define power as the relationship between energy and time. Its unit

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This unit is vacuum, but we can also use another unit such as steam horse.

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Sometimes we use power instead of energy.

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What is absolutely true is that the performance in a machine is always less than 10%.

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This is a consequence of the second principle of thermodynamics and it also happens.

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It always happens.

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And these are the most important contents that should be learned before studying machines.