Simple Machines (engineering)

There are six basic kinds of simple machines: the inclined plane, the wedge, the screw, the lever, the wheel and axle, and the pulley.

An inclined plane allows you to exert your input force over a longer distance. As a result, the input force needed is less than the output force. The input force that you use on an inclined plane is the force with which you push or pull an object. The output force is the force that you would need to lift the object without the inclined plane. You can determine the ideal mechanical advantage of an inclined plane by dividing the length of the incline by its height.

When you use a wedge, instead of moving an object along the inclined plane, you move the inclined plane itself. For example, when an ax is used to split wood, the ax handle exerts a force on the blade of the ax, which is the wedge. That force pushes the wedge down into the wood. The wedge in turn exerts an output force at a 90° angle to its slope, splitting the wood in two. The mechanical advantage of the wedge and the inclined plane are similar. The ideal mechanical advantage of a wedge is determined by dividing the length of the wedge by its width.

When you twist a screw into a piece of wood, you exert an input force on the screw. The threads of a screw act like an inclined plane to increase the distance over which you exert the input force. As the threads of the screw turn, they exert an output force on the wood, pulling the screw into the wood. Friction between the screw and the wood holds the screw in place. The mechanical advantage of a screw is similar to that of the inclined plane and wedge. The ideal mechanical advantage of a screw is the length around the threads divided by the length of the screw.

To understand how levers work, think about using a paint-can opener. The opener rests against the edge of the can, which acts as the fulcrum. The tip of the opener is under the lid of the can. When you push down, you exert an input force on the handle, and the opener pivots on the fulcrum. As a result, the tip of the opener pushes up, thereby exerting an output force on the lid. The ideal mechanical advantage of a lever is determined by dividing the distance from the fulcrum to the input force by the distance from the fulcrum to the output force.

How does a screwdriver make use of a wheel and axle to do work? When you use a screwdriver, you apply an input force to turn the handle, or wheel. Because the wheel is larger than the shaft, or axle, the axle rotates and exerts a large output force. The wheel and axle increases your force, but you must exert your force over a long distance. How does a screwdriver make use of a wheel and axle to do work? You can find the ideal mechanical advantage of a wheel and axle by dividing the radius of the wheel by the radius of the axle. (A radius is the distance from the outer edge of a circle to the circle's center.) The greater the ratio between the radius of the wheel and the radius of the axle, the greater the mechanical advantage.

You use a pulley by pulling on one end of the rope. This is the input force. At the other end of the rope, the output force pulls up on the object you want to move. To move a heavy object over a distance, a pulley can make work easier in two ways. First, it can decrease the amount of input force needed to lift the object. Second, the pulley can change the direction of your input force. For example, you pull down on the flagpole rope, and the flag moves up. The ideal mechanical advantage of a pulley is equal to the number of sections of rope that support the object.

2. Pulley

3. Wheel & Axle

4. Wegde

5. Incline plane

6. Screw
wedge- doorstop

inclined plane- ramp

screw- pencil sharpener

wheel and axle- tires

lever- crowbar

pulley- blinds

The six types of simple machines are

1) Lever

2) Pulley

3)Wheel and Axle

4)Screw

5)Inclined Plane

6) Wedge

All 6 simple machines: 1. Lever - a rigid bar, straight or curved, that is free to turn about a fixed point called the fulcrum. Ex. wheelbarrows, pliers, scissors, etc. The lever has three parts: * resistance force, or load - what is being moved or lifted * effort force - the force that the lever exerts, or the work done on the lever * fulcrum - the fixed pivot point 2. The Wheel and Axle - a machine where a large wheel is connected to a smaller whell or shaft called an axle. Ex. automobile steering wheels, doorknobs, gear wheels of the bicycle, screwdrivers, eggbeaters, meat grinders, pencil sharpeners, etc. Facts: * When either the wheel or the axle turns, the other part also turns. * One complete turn of the wheel produces one complete turn of the axle. * If the wheel turns but the axle doesn't, it is not a wheel-and-axle machine. 3. Pulley - A pulley is a wheel that turns around an axle. Usually, there is a groove in the rim of the pulley so that the rope around the pulley will not slip off. Ex. flagpole, etc. * A pulley may be fixed, movable or a combination of both called block and tackle. * The pulley is a modified lever. 4. Inclined Plane - a surface that is raised at one end. Ex. plank, the sloping floor of a theater or auditorium, a zigzag road up a mountain, stairway, etc. * It is a simple machine that gives us a gain in force. Less force is used in getting an object up to the higher end of an inclined plane than if the object is to be lifted directly from the lower level up to the raised end. The gain in force means a longer distance for the object to travel up an inclined plane. * The longer the inclined plane, the more gradual the slope becomes, and less force will be needed to move the object up the incline. * The shorter the inclined plane, the steeper the slope becomes, and more force will be needed to move the object up the incline. 5. Wedge - a form of inclined plane that tapers to a sharp edge.Ex. ax, knife blade, scissors blade, chisel, pin, nail, plow, etc. * It can be a sloping surface (a single inclined plane) or two sloping surfaces (a double inclined plane). * The wedge gives us a gain in force and also changes the direction of the force. * The longer or thinner the wedge, the greater the gain in force. 6. Screw - an inclined plane wrapped in a spiral around a cylinder post. A screw is composed of the body (the cylinder post) and the thread, which is the spiral ridge of the screw. The threads form a tiny ramp that runs around the screw from the tip to near the top. One complete turn of the screw moves it into the object a distance from one thread to another. The distance between two consecutive threads is called the pitch of the screw. The screw gives us a gain in force, but at the expense of distance. Ex. * nuts and bolts used to fasten things * drill bits used to make holes * jackscrews used to lift heavy objects * airplane propellers, helicopter blades and blades that screw through the air * propellers on boats that screw through the water * caps of jars * base of the electric light bulb * monkey wrench * clamp * vise * and etc.

You would probably use either an inclined plane or a pulley system.

An inclined plane is basically a ramp, so it would make it easier to push up to the top of a building. However, you'd need a REALLY big ramp for that, so you'd probably use a pulley: while you'd have to pull a lot of rope, it would let you lift a heavy object really easily.