It is a fixed point about which the simple machine moves or the point at which a lever pivots or hinges. The farther the effort is away from the fulcrum, the easier it is to move the load. If the distance from the effort to the fulcrum is greater than the distance from the load to the fulcrum, then the lever has a mechanical advantage. In other words, the ratio of these two distances is greater than one.

The axle is a rod of smaller radius fixed to the centre of the wheel which is of larger radius. This simple machine i.e wheel and axle is a combination of a wheel and an axle where the wheel moves as per the motion of the axle. A wheel and axle make it easy to move heavy things. Vehicles that run on wheels use wheel and axle.

Efficiency: Efficiency of a simple machine is its ability to convert the amount of energy supplied to it into work. Work done by the machine Efficiency = Work done by the machine Energy supplied Efficiency is usually written as a percentage: Efficiency = Workdone by the machine Energy supplied × 100 % Efficiency of any machine cannot be more than 100 % because a machine cannot do more work than the given supply of energy. Generally, efficiency of a machine is always less than 100 % because some energy is lost while operating the machine, such as energy loss due to friction .