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I. Sevila |  |
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| POWER | |
| In the majority of processes in which there is an energy exchange and/or work is done an important factor is the time taken in the process.
If we think about appliances like a refrigerator, a dryer, a light bulb which consume electric energy and transform it in order to cool, heat, illuminate..., the physical magnitude which relates the electric energy consumed in a unit of time is called power. Power applies to any process of energy transfer. So, for example, we can also talk of the power of a crane to lift a load, and the work performed by a hoist in the time unit. | |
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We know that the minimal force necessary to move an object is that which counteracts the forces which exist against the direction of the movement. This is equal to finding a force which cancels out the resultant force acting on the object.
A very frequent situation found in building projects is the use of cranes. It is essential to know the magnitude of the load we are going to lift in order to choose the crane. Power is an important question. | |
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