Machines: Definition, Examples, And Applications

Machines: Do you know we can easily lift heavy loads with a small effort? Do you know we can make the work easier with the help of the machines? Without machines, we need a large effort to do the same work. With machines, we can change the direction of force and direct the effort in the required direction. Machines are also very useful to reduce the risk of hazardous tasks. So, humans have developed devices and tools to make work easier. This article will study an inclined plane, the wheel and axle, the pulley, the lever, the screw, and the wedge.

Simple Machines

Simple machines are that mechanical devices that can change the direction or magnitude of a force. It is a device that helps us do work by applying less effort, speeding up motion, applying force at a convenient point, or reducing the risk in a hazardous task. They use leverage or mechanical advantage to multiply force. It has few or no moving parts. We can classify simple machines into the following form after modification into many other simple machines:

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Lever

It is used to pry objects loose and also used to lift objects. A lever can rotate about a fixed point or a fixed line called the axis of rotation. This axis of rotation is called the fulcrum of the lever. The effort arm is the distance from the applied effort to the fulcrum. The load arm is the distance from the applied load to the fulcrum. The arm of the lever turns against a fulcrum. As we exert a force on one end of the pivot, it creates a force on the other end of the lever. We can either increase or decrease the applied force based on the distance from the fulcrum to the effort and from the fulcrum to the load. Examples of levers in everyday life include teeter-totters, wheelbarrows, scissors, pliers, bottle openers, mops, brooms, shovels, nutcrackers.

Pulley

A pulley is a simple machine that has a flat circular disc with a groove on its edge. It can rotate around a fixed point passing through its central axis (axle). An axle is connected to a frame or a block. It is used to change the direction of the force very easily. The cord can move in either direction when the wheel rotates. A single fixed pulley has its axis of rotation fixed and hence is called a fixed pulley. For instance: To hoist a flag on a flag pole, we use a pulley in which a rope is attached to it to raise and lower the flag more easily.

Inclined Plane

A sloping flat surface along which a load can be easily pushed or pulled is known as an inclined plane. It makes it is easier to lift objects to greater heights. It is a simple machine that has a mechanical advantage always greater than one. For an inclined plane, the mechanical advantage is defined as the ratio of the load to the effort. To lift an object straight up requires a greater force to be exerted, but an inclined plane requires a smaller force to lift it, but the effort should be exerted over a long distance. Some everyday examples of inclined planes are ramps, sloping roads, chisels, hatchets, inclined conveyor belts, carpenter’s planes, wedges, etc. 

Wedge

A wedge is a double inclined plane.  We can get a wedge by joining two inclined planes together to form a sharp edge. We can break apart substances by using wedges simply by applying force on them.  A common example of a wedge is a nail in which the force is applied to the wide head area of the nail. When we apply a force, it gets concentrated in a small area where the force is exerted. Then, the force is magnified at this point and pierce through objects. As the nail sinks into the object, it moves forward and forces the object apart. 

Screw

A rod or nail with grooves on its circular curved surface and holds two objects firmly together is a screw. Threading around the shaft in a screw makes it an efficient tool to keep things together. The main function of the threads is to hold the surrounding material like teeth by using grip securely. Some examples of screws are screw, bolt, spinning stool, and spiral staircase, etc.           

Wheel and Axle

We can make our work easier by moving objects across distances with the help of a wheel and axle. It consists of two cylinders of different radii joined together, such that if one is made to rotate, the other rotates. We can also greatly reduce the friction involved in moving an object by using a wheel and axle. When the wheel turns with the axle, it causing movement. The wheel is one of the most significant inventions that make work easier than before. Before the invention of wheels, the amount of load and the distance we could carry the load over land was limited. For example, with the help of the wheels, it is easier to roll a \(2000\) kilogram block of stone rather than pushing or lifting it.

Compound Machines

We can get a compound machine after combining two or more simple machines. For example, let us consider a wheelbarrow. It is a compound machine. In which the wheel and axle are combined with that of a lever. We can get many compound machines by using six basic simple machines. The opener, shovel, and jack are some examples of compound machines.

Summary

Simple machines generally have few or no moving parts. It modifies the motion and the magnitude of a force to perform work easier. The inclined plane, lever, wedge, wheel and axle, pulley, and screw are simple machines. An inclined plane is used to raise heavy bodies. It consists of a sloping and flat surface. When a lever rests on a support, it is called a fulcrum. It is used to lift a heavyweight with a small force. A wedge is a double inclined plane that tapers to a thin edge. When we push the wedge in one direction, it creates a force in a lateral direction. A wheel and axle are simple machines in which a circular frame (the wheel) revolves on a shaft or rod (the axle). A pulley is a wheel used to transmit energy and motion that consists of a strong and flexible rope, cord, cable, chain, or belt on its rim. A screw is a circular cylindrical member with a continuous helical rib. We can use a screw either as a fastener or as a force and motion modifier.

FAQs on Machines

Q.1. Why are simple machines important?
Ans: Simple machines are important because they reduce the effort by making the work easier. It can extend the ability of people to perform tasks beyond their normal capabilities. Simple machines are widely used include the wheel and axle, pulley, inclined plane, screw, wedge, and lever.

Q.2. How to move heavy objects with the help of a lever?
Ans: We can easily move heavy objects with the help of a lever. When we push down one end of a lever, the other end moves up in the opposite direction, like a seesaw. Moving to the fulcrum close to the object you want to lift makes it easier. 

Q.3. Explain how an inclined plane or pulley works to change the amount of force required to move an object. 
Ans: To raise a load or object, we generally use inclined planes and pulleys. The main function of the inclined plane is to reduce the amount of force required by increasing the distance of an object. And the function of the pulley is to change the direction of the force.

Q.4. How would you justify how simple machines change the amount of force required to lift or move a load?
Ans: The function of the simple machine is to change the magnitude of a force or the direction of a force. They use mechanical advantage, also known as leverage, to multiply the force exerted on a load. One of the trade-offs with simple machines is that as the amount of force required to lift a load decreases, there is a proportional increase in the distance that the load must be moved.

Q.5. How can you distinguish between a wedge and an inclined plane?
Ans: Wedges are those simple machines with one flat edge and are used for cutting, while inclined planes have two flat edges and are used for moving objects from one level to another.

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