Efficiency of a simple machine can be increased by reducing the friction. But oiling and greasing the machine is a useful way to increase the efficiency of a machine.

Answer. The definition of a perfect machine states that a perfect machine should be 100% efficient which means the 100% of the energy input should be transformed into work output. For these reasons,we cannot expect perfect machines in the real life situations.

bicycle

First- and second-class levers generally are very efficient, especially when the loads are located close to the fulcrum while efforts are further from the fulcrum (Figures A and C). The efficiency of first- and second-class levers will decrease when loads move further from the fulcrum (Figures B and D).

Definition of effort (ε). The resistive or opposing force to be overcome by a machine is called the load (L).

There are three ways simple machines make work easier: by increasing the distance through which force is applied, by changing the direction of applied force, or by multiplying force of speed of the energy applied. Turning the wheel a greater distance produces a short and more powerful movement at the axle.

Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever. While simple machines may magnify or reduce the forces that can be applied to them, they do not change the total amount of work needed to perform the overall task.

wedge

simple machine: A machine with few or no moving parts that is used to make work easier (provides a mechanical advantage). For example, a wedge, wheel and axle, lever, inclined plane, screw, or pulley.

lever

The six simple machines are the wedge, screw, lever, pulley, inclined plane and the wheel and axle. They all make work easier and have few or no moving parts.

Using a system of pulleys can be much more complex and provide a powerful mechanical advantage — greatly reducing the amount of force required to move an object. If one movable pulley is used (Figure 6), the amount of force required to raise the object attached to the movable pulley is cut in half.

A screw is a special kind of inclined plane. It’s basically an inclined plane wrapped around a pole. Screws can be used to lift things or to hold them together.

pulley. a grooved wheel with a rope wrapped around it.

A screw is an inclined plane wrapped around a cylinder.

An inclined plane, also known as a ramp, is a flat supporting surface tilted at an angle, with one end higher than the other, used as an aid for raising or lowering a load. The wedge can be considered a moving inclined plane or two inclined planes connected at the base.

inclined planes

screw