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Thesimple machines They are those devices that allow changing the intensity or direction of the energy that reaches its entry point in the form of mechanical work, and whose components are all rigid solids.
The simple machinesare used to multiply force or, as noted, to change your address; The idea is always that the work requires less effort and that it is then easier, and sometimes also safer. In sum, simple machines are used to transform or compensate a resistant force or lift a weight in more favorable conditions.
In the so-called mcompound corners, the benefits of two or more simple machines are combined.
Simple machines arose to solve the problems posed by the daily activities in ancient times, including hunting, fishing or the transport of heavy objects. In truth, certain utensils were first designed, which were later perfected and that is how the first simple machines emerged. You could say that those early machines functioned almost like a extension of human hands: they were wooden instruments for digging, sharp rocks for cutting and others. But without a doubt, they produced important changes in the history of man and in his relationship with work.
Simple machines include those that have a single point of support (what varies between them is the location of said support) and take advantage of some basic physical principles as moment of a force, work, power, energy Y mechanical performance. It should be borne in mind that simple machines do not escape the law of conservation of energy: energy is neither created nor destroyed in the simple machine, it is only transformed.
There are 6 simple machines
- Lever
- Pulley
- Inclined plane
- Cradle
- Wheels and axles
- Screws
The lever, one of the most important, is a rigid bar that can rotate around a fixed point, the fulcrum. The force applied to the lever is called the motive force or power and the force that is overcome is known as resistanceto. The length of the lever is important to overcome resistance
The pulley It is used to raise heavy objects to a certain height. It is a wheel through which a rope passes on the outside; at one of the ends of said rope a weight or load, what rises when a greater force is applied to the other end. It serves both to reduce the force required to lift objects and to change direction. exist simple pulleys and others formed by several wheels; the latter are called rigging.
At inclined plane what happens is that the force of weight breaks down into two components. Thus, the effort required to lift the load is less.
The cradle is a body where two converge somewhat sharp inclined planesThis creates a lacerating point of contact, which allows cutting or tearing solid objects.
The wheel is a round body that rotates about a fixed point, called axis of rotation, usually cylindrical. It is used to transmit a rotary movement between axes, to facilitate the movement of objects and people, etc.
The screw it's just a inclined plane screwed in spiral, each of the turns is called thread. For a screw to enter a body through its surface it goes spinning, the force required to make each turn and complete the process is always less than that required to nail it in a straight line.
Examples of simple machines
Many, many objects from everyday life, which we use to travel, to play or in the world of work, are based on one or more of these six well-known machines. Twenty simple machines are listed below as an example:
- Norias: They allow the extraction of water through the fundamental principle of the hydraulic rosary. It is placed partially submerged and through continuous movement enables the extraction of water.
- Water pumps: Device that lifts, transfers and compresses liquids. Use the fundamental principles linked to pressure.
- Cranes: By means of the lever effect, it manages to lift weight by means of a beam, thus making less amount of force, manipulating it with pulleys on a rotating pivot that allows horizontal movement. The stability of the crane makes it indispensable for the construction industry.
- Slide: It uses the fundamentals of the simple 'inclined plane' machine, where potential energy is used, the concepts of speed and acceleration are involved, and it is assumed that there is no friction force (or that this is minimal).
- Up and down: The lever effect is combined in this popular game with the inclined plane, uniting two simple machines in one, and taking advantage of both the weight and the force of gravity, based on a point of support, before the action of the force and reaction of a resistance.
- Wheelbarrow: Common in the construction area, managing to distribute the weight by directing it towards the rim, which makes it possible to support a much greater weight with the sole effort of pushing the truck.
- Gear: Toothed wheel that makes an object move faster or slower, by manipulating the force necessary to move it.
- Turnstile: Combination of a crank and a cylinder, which allows lifting a heavy body by means of a much lower force.
- Ax: Essential to separate or lacerate (firewood, for example), it has a piece of metal finished in the shape of a wedge, which is what tears and allows cutting.
- Scissors: Typical example of a simple lever, which combines strength and power to achieve its task, that of cutting by joining the two steel blades.
- Cistern: Use the pulley to raise or lower the bucket, thus raising the mass of water by transforming energy.
- Endless screw: Inclined plane screwed around a rod, which when it rotates, manages to insert the thread (an inclined plane) into a wood, thus keeping two things together with minimal effort.
- Pincers: Example of the lever, similar in application to the scissors.
- Nutcracker: Combination lever of power and resistance, which allows applying the force on the exact point to split the nut.
- Rod: Using the human arm as a fulcrum, the lever manipulates force. The improvement of the fishing rods made the task less and less difficult.
- Roman balance: Instrument that measures masses, and that is fundamentally based on levers.
- Guillotine: Simple machine formed by a very sharp blade, today it is used more than anything to cut a large quantity of papers at the same time.
- Knife: Applies the mechanisms of the inclined plane achieving by means of the cutting edge, usually food or ropes.
- Cranks: Tool used to transform rectilinear motion into circular motion, or vice versa. It is used to rotate a shaft with less effort (something that was very necessary in old cars).
- Bike: Apply the foundation of the wheel and axle to allow the load (the person on the bike) to shift.
