⇒ A machine is only useful if it can effectively convert one form of energy into another form of energy
⇒ The total outputted energy from a machine is always equal to the total amount of energy put into the machine. However, not all of the output energy will be useful
⇒ Some of the input energy will be lost or wasted as other forms of energy other than purely useful energy (such as heat)
⇒ The less energy that is wasted, the more efficient something is
⇒ The efficiency of a machine is defined as:
⇒ To determine how efficient something is, you must first find how much energy was originally supplied to it (i.e. the total energy input)
⇒ Then, you must find how much of that energy was output as useful energy
⇒ You can then work out how efficient the object was by dividing the smaller number by the large one, to produce a value for efficiency between 0 and 1