Оправдание topic simple machines. Методическая разработка занятия по английскому языку на тему "Машины и работа" (3 курс)

Simple machines can be used to make work easier and faster. Compound machines are basically simple machines placed together to work together. Work is force acting on an object that moves it a distance (W=F*d). A simple machine must have some force applied to it to do work. Simple machines let us use a small force to beat bigger forces. They can also change the direction of the force. Keep in mind that a simple machine cannot create energy (F input * d input = F output * d output). If you want the force output to be big and distance output to be small, you need to have a big distance input and a small force input. If you want the force output to be small and the distance output to be large, then the force input needs to be large and the distance input to be small (Fd = Fd). There are three simple machines will be focus on for this project: lever, pulley, and wheel and axle. .
The lever is used in seesaws, shovels, hammers, and other everyday objects. A lever consists of three main parts: the fulcrum, rod, and the load the machine is acting on it. The fulcrum, or fixed point, allows the rod to move up and down freely. There are three classes of levers, but for this project a will be using the second-class lever. This lever allows us to use less force to act on the load. In other words, less force and more distance will be inputted to result in more force and less distance. This kind of lever in usually used to move heavy objects. The fulcrum is closer to the load to achieve this. This simple machine will probably be the best to lift the soda can. Most of the lever can be built out of wood. The fulcrum may be made out of metal or wood. .
The pulley is used in cranes. Pulleys usually lift the load. A pulley changes the direction in the force to do that. A pulley is used to change the direction of the force. It can also multiply forces depending on the type. In this project a type one and two pulley will be used.

Essays Related to Simple Machines

1.

Technology and machines have become more advanced we have grown accustomed to having machines such as computers and cars in our everyday lives. Our own machines will soon surpass our own intelligence. ... Machines have played a vital role in our lives. ... When they were first created a computer that had the power of one of today"s simple five dollar calculators required so much space to hold all of their necessary equipment it could take up a whole room, but the simple machine known today can be made so small it can not even be handled by a human due to its s...

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AI is the attempt to make machines, specifically computers, perform intelligently through programming. ... It could be said that the human brain is nothing more than a machine, and as we know it to be capable of thought it would be fair to surmise that therefore machines can think and it is probably this, or a similar premise that inspired AI. ... This argument is an attempt to demonstrate that although a computer program appears to be understanding a story, it is merely obeying simple instructions, and has no understanding at all. ... But what are these natural causal properties, and from ...

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3.

In The Time Machine by H.G Wells, Wells portrays the future to an exact detail. ... The Eloi are simple and beautiful creatures, but the Time Traveler thinks of them as weak and lazy. ... Through the Time Machine Wells warns that mankind will come to end if capitalism continues. ... Social Darwinism and evolution are presented throughout the Time Machine. ... Well"s uses the Time Machine to project what he believes the future will be. ...

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• Grade Level: High School

4.

Rage Against The Machine At first thought a band standing on stage naked for 15 minutes without saying a word or playing a single note might seem lewd, but after finding that they were silently protesting censorship one might think differently of them. Rage Against the Machine (RATM) is probably one of the most atypical bands that one could ever find. ... Believe it or not there are bands who care less about money and more about issues and Rage Against the Machine is one of them. ... The majority of their songs were primarily written as activist poetry by Zack de la Rocha (lead singer ...

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ABSTRACT Complex system theory in animals and machines is well developed and a basic synopsis is provided. ... These ideas have been applied in the field of Engineering to develop machines for controlling states of objects or events: a simple temperature control system is used as a model. ... This process, is the modern basis of the modern theory regarding the evolution of life, which in simple terms can be described as the process of prolonging a type of structure through; duplication, reproduction or other processes. ... A basic comparison of control systems in nature and machines can b...

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6.

Personally thinking, technology makes people"s life simpler than making people"s lives more complicated because newly developed devices, improvement of living condition and efficient transportation. ... All of those technologies can help people get a simpler and easier lives. ... Thus, technology has more benefits can be discovered, and it make lives simpler rather than more complicated. In conclusion, although technology may be a little bit complicated, when we count it use on machines, communication, information, and transportation, it is more pure and effortless for our lives. ...

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A simple distinction between both groups is that humans depend on organization where as animals do not. The Time Machine by H.G. ... Unlike the Eloi, the Morlocks have a curiosity for knowledge which is why they take the time machine. ... When the time machine is returned to him, he notices that it is very clean and well oiled. ... Wells illustrates this quite well in The Time Machine. ...

). The steeper the slope, or incline, the more nearly the required force approaches the actual weight. Expressed mathematically, the force F required to move a block D up an inclined plane without friction is equal to its weight W times the sine of the angle the inclined plane makes with the horizontal (θ). The equation is F = W sin θ.

The principle of the inclined plane is used widely-for example, in ramps and switchback roads, where a small force acting for a distance along a slope can do a large amount of work.

The

A lever is a bar or board that rests on a support called a fulcrum. A downward force exerted on one end of the lever can be transferred and increased in an upward direction at the other end, allowing a small force to lift a heavy weight.

All early people used the lever in some form, for example, for moving heavy stones or as digging sticks for land cultivation. The principle of the lever was used in the swape, or , a long lever pivoted near one end with a platform or water container hanging from the short arm and counterweights attached to the long arm. A man could lift several times his own weight by pulling down on the long arm. This device is said to have been used in Egypt and India for raising water and lifting soldiers over battlements as early as 1500 bce .

The

A wedge is an object that tapers to a thin edge. Pushing the wedge in one direction creates a force in a sideways direction. It is usually made of metal or wood and is used for splitting, lifting, or tightening, as in securing a hammer head onto its handle.

The wedge was used in prehistoric times to split logs and rocks; an is also a wedge, as are the teeth on a saw. In terms of its mechanical function, the screw may be thought of as a wedge wrapped around a cylinder.

The

A wheel and axle is made up of a circular frame (the wheel) that revolves on a shaft or rod (the axle). In its earliest form it was probably used for raising weights or water buckets from wells.

Its principle of operation is best explained by way of a device with a large and a small gear attached to the same shaft. The tendency of a force, F , applied at the radius R on the large gear to turn the shaft is sufficient to overcome the larger force W at the radius r on the small gear. The force amplification, or , is equal to the ratio of the two forces (W :F ) and also equal to the ratio of the radii of the two gears (R :r ).

If the large and small gears are replaced with large- and small-diameter drums that are wrapped with ropes, the wheel and axle becomes capable of raising weights. The weight being lifted is attached to the rope on the small drum, and the operator pulls the rope on the large drum. In this arrangement the mechanical advantage is the radius of the large drum divided by the radius of the small drum. An increase in the mechanical advantage can be obtained by using a small drum with two radii, r 1 and r 2 , and a pulley block. When a force is applied to the large drum, the rope on the small drum winds onto D and off of d.

A measure of the force amplification available with the pulley-and-rope system is the velocity ratio, or the ratio of the at which the force is applied to the rope (V F ) to the velocity at which the weight is raised (V W ). This ratio is equal to twice the radius of the large drum divided by the difference in the radii of the smaller drums D and d. Expressed mathematically, the equation is V F /V W = 2R /(r 2 - r 1). The actual mechanical advantage W /F is less than this velocity ratio, depending on friction. A very large mechanical advantage may be obtained with this arrangement by making the two smaller drums D and d of nearly equal radius.

The

A pulley is a wheel that carries a flexible rope, cord, cable, chain, or belt on its rim. Pulleys are used singly or in combination to transmit and motion. Pulleys with grooved rims are called sheaves. In , pulleys are affixed to shafts at their axes, and power is transmitted between the shafts by means of endless belts running over the pulleys.

One or more independently rotating pulleys can be used to gain mechanical advantage, especially for lifting weights. The shafts about which the pulleys turn may affix them to frames or blocks, and a combination of pulleys, blocks, and rope or other flexible material is referred to as a . The Greek mathematician (3rd century bce ) is reported to have used compound pulleys to pull a ship onto dry land.

The

A screw is a usually circular cylindrical member with a continuous helical rib, used either as a fastener or as a force and motion modifier.

Although the Pythagorean philosopher (5th century bce ) is the alleged inventor of the screw, the exact period of its first appearance as a useful mechanical device is obscure. The invention of the is usually ascribed to Archimedes, but evidence exists of a similar device used for irrigation in Egypt at an earlier date. The screw press, probably invented in Greece in the 1st or 2nd century bce , has been used since the days of the Roman Empire for pressing clothes. In the 1st century ce , wooden screws were used in wine and olive-oil presses, and cutters (taps) for cutting internal threads were in use.

Are made in a wide variety of diameters and lengths; when using the larger sizes, pilot holes are drilled to avoid splitting the wood. are large wood screws used to fasten heavy objects to wood. Heads are either square or hexagonal.

Screws that modify force and motion are known as . A screw jack converts (turning moment) to thrust. The thrust (usually to lift a heavy object) is created by turning the screw in a stationary nut. By using a long bar to turn the screw, a small force at the end of the bar can create a large thrust force. Workpiece tables on are moved linearly on guiding ways by screws that rotate in at the ends of the tables and mate with nuts fixed to the machine frame. A similar torque-to-thrust conversion can be obtained by either rotating an axially fixed screw to drive a rotationally fixed nut along the screw or by rotating an axially fixed nut to drive a rotationally fixed screw through the nut.

The wheel and axle , the inclined plane , the wedge , the , and the screw . Several of these simple machines are related to each other. But, each has a specific purpose in the world of doing work.

There are special tools for measuring the force necessary to move an object. These are known as force meters. They use a spring and a hook to determine how much pull is required to slide an object up an inclined plane. Really very simple to use.

Compound Machines

Simple machines can be combined together to form compound machines. Many of our everyday tools and the objects we use are really compound machine . Scissors are a good example. The edge of the blades are wedges. But the blades are combined with a lever to make the two blades come together to cut.

A lawnmower combines wedges (the blades) with a wheel and axle that spins the blades in a circle. But there is even more. The engine probably works in combination of several simple machines and the handle that you use to push the lawnmower around the yard is a form of a lever. So even something complicated can be broken down into the simplest of machines.

Take a look around you — can you figure out what simple machines make up a can opener, the hand cranked pencil sharpener, the ice dispenser in the refrigerator or the stapler? Just be careful, though. In our modern times, many things rely on electronics and light waves to function and are not made of simple machines. But even then, you may be surprised. The turntable in your microwave oven is a wheel and axle. The lid to the laptop is connected to the pad by a hinge or lever.

Simple machines may be simple — but they are simply everywhere.

A Word or Two About Rube

Rube Goldberg was a famous cartoonist who lived between 1883 and 1970. His life was spent creating art and sculptures, but his most famous work was for his "inventions." These inventions were a series of simple machines put together in a complex fashion to accomplish something very simple, but it took many steps to get there. Contests have been run for many years since Mr. Goldberg first created his unique ideas. In the contests people try to come up with new ways to turn on a light, or start a toaster using these combinations of the simple machines to wow judges and audiences for their unique way of doing these simple tasks.

Rube Goldberg machines are fun to watch and to build. Visit this site for some fun — see if you can identify each of the simple machines as they work together in this animation of a Rube Goldberg gadget designed to get this guy out of bed in the morning. Click .

For more information about Rube Goldberg"s life and his art, click .

A simple machine is a mechanical device that consists of a minimum of moving parts but yet can create an improvement of the output over the input. The improvement could be creating a mechanical advantage or simply changing the direction of the output. Mechanical advantage is the increase of force, distance or speed from the input value.

Around the 16th century, the classic list of simple machines was determined. The list consisted of the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

These simple machines can be broken into three classifications: lever simple machines, rotating simple machines, and inclined plane simple machines.

Questions you may have include:

• What do lever simple machines do?
• What do rotating simple machines do?
• What do inclined plane simple machines do?

This lesson will answer those questions. Useful tool: Units Conversion

Lever simple machines

The lever simply consists of a rod or board that pivots on a fulcrum, creating a mechanical advantage or a change in direction.

The lever is a classic simple machine that achieves a mechanical advantage according to the ratio of the output or load arm of the lever divided by the input or effort arm.

The mechanical advantage of a lever can concern force, distance, or speed of the output.

The efficiency of the lever is very high, since the loss due to friction at the fulcrum is low.

Rotating simple machines

Rotating simple machines include rollers, wheel and axle, crank, and pulley.

Rollers

The wheel or roller by itself can make it easier to move objects by overcoming friction.

Wheel and axle

When an axle is added to a wheel, a torque on the axle increases the speed of the outer surface of the wheel. Likewise, turning the wheel from its outer edge increases the force applied from the axle.

Crank

A crank is like a wheel and axle. You can push on the handle of a crank, and it will create a twisting force or torque on the axle. This is a variation of the wheel and axle.

Pulley

A pulley is a wheel and axle, that uses a rope to lift objects. A major purpose of a pulley is to change the direction of the input force. You can pull down one a pulley rope, and the rope will lift the object upward.

Complex set of pulleys

A complex set up pulleys, such as a block-and-tackle configuration, can result in a mechanical advantage. The question is that if it is a complex set, is it still a simple machine? Probably not.

Inclined plane simple machines

Variations of an inclined plane include a ramp, wedge, and screw.

Ramp

The inclined plane or ramp makes raising a weight to a given height easier, according to the angle of the incline. Unfortunately, the resistive force of friction from sliding the object on the ramp can negate the mechanical advantage.

Variations of the inclined plane are the wedge and screw.

Wedge

Although a wedge is considered a simple machine, it is really a special application of an inclined plane.

Screw

The screw is really an inclined plane that is wrapped around a shaft. Turning the shaft around its central axis transforms rotational motion and torque into axial motion and force.

A screw can also act like a wedge, forcing itself into a softer material.

Summary

Simple machines usually exchange using a smaller force over a greater distance to move a heavy object over a short distance. The work required is the same, but the force required is less. The are also simple machines that help to reduce the resistance of friction or such.

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