A single fixed pulley has a mechanical advantage of 1:1. Mechanical advantage, which is correlated to the usefulness of a machine, refers to the proportion of force output to force input. Force output refers to the force exerted by the machine, while force input refers to the applied force.Continue Reading
Machines are devices that utilize mechanical or electrical power to perform a variety of functions. Mechanical machines are contraptions that increase work capacity and efficiency by providing added energy to carry out certain activities.
There are two classifications of mechanical machines: simple and compound. Simple machines are composed of a single mechanical apparatus. The six types of simple machines include the wheel and axle, simple lever, simple inclined plane, pulley, wedge and screw.
A pulley consists of a wheel having a corrugated rim with a length of rope, string, cord or chain running along the rim. This simple machine is typically used to hoist or lower down a load, particularly heavy objects.
The mechanical advantage of a pulley system is determined by the number of ropes hanging on the sides of all pulleys that are working against gravity. A single fixed pulley uses only one rope, where the load is lifted by the same distance as the other end of the rope is pulled down. In a 1:1 mechanical advantage, the applied force is the same regardless of the pulley being used.Learn more about Motion & Mechanics
A compound pulley, sometimes referred to as a block-and-tackle system, is a mechanical arrangement of pulleys that permits a trade-off of applied force for distance, according to HowStuffWorks. By slinging rope over and through a system of wheels, a compound pulley permits weights to be lifted and pulled with the application of relatively little force, saving energy and reducing the power needed to accomplish work.Full Answer >
A pulley works by changing the direction that force must be applied to lift an object against gravity. Other, more complex, systems use multiple pulleys to reduce the amount of force that must be applied.Full Answer >
A movable pulley is a pulley that can freely move. This is only one of three types, the other two being fixed and compound pulleys. Examples of movable pulleys are elevators.Full Answer >
According to Jibbaroo, to make a compound pulley system, you need two wheels from a K'nex set, seven paper clips, tape, string and a 1- to 3-pound hand weight or an unopened can of food. Jibbaroo provides the steps needed to construct the pulley system.Full Answer >