Simple machine pulley

There is generally considered to be five distinct simple machines lever, wedge, wheel and axle, pulley, and screw. The transmission of energy by these simple machines is so basic that people use them with little understanding of the physical principles involved. Most learn their use intuitively, through experience, and consider their application just plain common sense. 

A pulley is a simple machine consisting of a grooved wheel through which a rope runs. The pulley can be thought of as a kind of lever if one thinks of the grooved wheel as the fulcrum of the lever. Then the effort force is the force applied on one end of the pulley rope, and the resistance force is the weight that is lifted at the opposite end of the pulley rope. 

A simple machine is a basic device used to make work easier. Work is the transfer of energy from one physical system to another. During this process, energy is not created, only transferred. There are six simple machines inclined plane, wedge, screw, lever, wheel and axle, and pulley. We discuss each simple machine separately in this chapter. If we combine two or more simple machines so that they function together to make work easier, the device is called a compound machine. A wheelbarrow is an example of a compound machine it incorporates two simple machines (the lever and the wheel and axle). 

There are six simple machines inclined plane, wedge, lever, pulley, screw, and wheel and axle. 

Applied physics is of necessity the oldest of all practical sciences, dating back to the first artificial use of an object by an early hominid. The basic practices have been in use by builders and designers for many thousands of years. With the development of mathematics and measurement, the practice of applied physics has grown apace, relying as it still does upon the application of basic concepts of vector properties (force, momentum, velocity, weight, moment of inertia) and the principles of simple machines (lever, ramp, pulley). 

B.C.E. Pulley Described by Archimedes, the puUey is a simple machine that allows one to change the direction of the force dehvered to the load. 

From those tools and the concepts associated with them came some of the first simple machines, e.g., the pulley, bellows, screw, and the first use of gears. Those were followed by the water wheel, windmill, mechanical clock, lathe, the first pumps, and the printing press with movable type, among hundreds of others. 

Most modern machines can be traced back to the five basic machines described by the Greek inventor Hero of Alexandria who lived at about the time of Christ. The machines described by him were the wedge, the screw, the wheel and axle, the pulley, and the lever. Originally they were used for simple purposes, to raise water and to move objects which man alone could not lift, but today their principles are of fundamental importance to our scientific understanding of mechanics. Let us now consider some fundamental mechanical principles and calculations. 

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