We know that the law of conservation of energy states that energy can not be created or destroyed. It only changes form. Conside
r this energy transformation diagram. Assume that the energy input in this case is chemical potential energy and the useful energy output is kinetic energy, specifically a small fan to keep you cool. The diagram also shows how to calculate the efficiency of the fan. If the law of conservation of energy holds true, explain why the efficiency of the fan is not 100%.
The conservation of energy always holds true even when not clearly observable in machines that are less than 100% efficient. More often than not a machine will suffer energy losses (e.g. consider for a cooling fan: friction between the rotating blades, drag resistance in the air the fan is pushing around, resistance in the wire, and heat radiating/conducting away from the circuitry).
The law of conservation of energy states that energy can neither be created nor be destroyed. It can only change its states from one energy state to another.
The efficiency is defined as the ratio of output work to the input work. The efficiency of the fan is not 100%. Because some of the energy is lost in the form of heat and sound. No machine is 100% efficient. There is always some loss of energy takes place.
