- Inclined plane
:"This article deals with the physical structure. For related terms, see
canal inclined plane, cable railway, funicular, or fixed-wing aircraft(airplane).", but the inclined plane allows the same work to be done with a smaller force exerted over a greater distance.
Ramps, Chutes and Slides
An inclined plane is a simple machine with no moving parts. Many devices based on the principles of the inclined plane allow expending less force to achieve a task.
Ramps enable accessing heights that would be too difficult to scale vertically. Ramps allow heavy chickens to ascend to, and descend safely from, a high-level bridge. Portable ramps allow easy loading and unloading of high-decked trucks. Siegeramps gave ancient armies the ability to walk up bringing heavy equipment to the tops of high walls. chutes and Slides allow fragile objects, including humans, to be safely lowered from a vertical rise by countering gravitational force with the normal forceprovided by a stiff surface at an angle to the gravitational vector. Airplane rescue slides allow people to quickly reach the ground safely, without the danger of jumping from a height. The addition of the normal force and gravity vectors causes the sliding object to move parallel to surface of the slide, so a slide can be used to move objects through a distribution system from one area to another. Hoppers and funnels are formed by planes shaped into an inverted pyramidor coneshape to concentrate granular or fluid material at the apex.
frictionfrom a slide increases the maximum speed at which an object can move down the slide, while the acceleration of the moving object can be controlled to any degree by varying the angle of the slide. Because of this, slides are one of the most common and popular forms of entertainment. A well-polished slide can allow a human to move at a high speed with no effort, even experience near free-fallacceleration, yet arrive on the ground safely because the angle of slide can be varied along its length to end up parallel to the ground, so the forward motion of the slider can be slowly arrested by friction. The metal slide is a popular piece of playground equipment, and towering water slidesemploy liquid lubrication to reduce friction even further. Wheeled cars of rollercoastersroll down inclined tracks to achieve high speeds. In the sports of Luge, bobsled, sledding, and skiing, participants accelerate to extremely high speeds utilizing only the inclined plane, whether a mountain slope provided by nature, or a chute lined with near-frictionless ice.
Blades, Wedges, and Foils
bladeis a compound inclined plane, consisting of two inclined planes placed so that the planes meet at one edge. The edge where the two planes meet is pushed into a solid or fluid substance and overcomes the resistance of materials to separate by transferring the force exerted against the material into to opposing forces normal to the faces of the blade. First known to be used by humans in the knifeto separate animal tissue, the blade allowed humans to separate meat, fibers, and other plant and animal materials, with much less force than it would take to tear them by simply pulling them apart. Blades can separate solid material, as with plowsthat separate soil particles, scissorsand shearsto cut flexible materials, axesto separate wood fibers, and chiselsand planesto remove precise portions of wood. Wedges, saws and chiselscan separate thick and hard materials, such as wood, including solid stone and hard metals, with much less force, less waste of material, and more precision, than crushing. Saws have many chisel-like "teeth" along their cutting surface to transfer linear or circular motion to counteract the normal force of the surface to be cut.Crushing, the overcoming of material bonds by transferring momentumto a material through the normal forceof another, harder, object was the only way to cut through a hard material before saws, and the materials to make them, were developed. Drillsproduce circular holes in solids by rotating a chisel around its center, with the edge is sharpened at opposing angles on either side of the rotation axis, so as to cut in the direction of rotation. Twist drills provide one or more heliacally twisted chisels formed out of grooves cut along the side of the bit, to help evacuate cuttings from the drill hole, by using the same inclined plane principle as the archimedean screw. The water screw, though most likely preexisting Archimedes, has been used since ancient times to pump water, and is now also used to move granulated and ground materials, such as wheat, coal, and meat. Screws also join pieces of wood or metal together, by using a helical plane, usually formed by cutting a helical groove into a rod, to allow the rod force itself into the material when it is rotated.
water wheeluses inclined planes mounted around a rotating wheel to transform the momentum of moving water into a torquethat can turn a shaft and do work. Sailsextract the momentum of moving air to drive a vehicle, and windmillsextend the principle to move a balanced set of sails around a shaft to perform work. Although known for thousands of years, these devices for extracting work from a moving fluid were always limited in efficiency by the drag-inducing vortices caused when a fluid is separated. Foils are specialized blades, shaped to allow the most efficient movement of fluid over their surfaces, to minimize the turbulencecaused by these vortices. Rotating vortices dissipate the momentum of the fluid as heat, reducing the amount of energy available to do useful work.
Foils have many different designs, depending on the
viscosity, velocity, and pressureof the fluid they will operate in, and their intended purpose. Aircraft wingsand helicopterrotors counteract gravity by redirecting momentum generated from lateral movement, as with fixed-wing aircraft, or from rotating airfoils around a shaft, as with helicopters, so that separated air flows over the top of the foil faster than it flows over the bottom. This difference in velocity causes the pressure to increase on the bottom, generating a lifting force, through what is known as Bernoulli's Principle. The same principle in reverse allows an automotive spoilerto keep a car firmly in contact with the road.
Airplane and marine
propellers use the same principle to drive vehicles though a fluid along the direction of the torque applied to the propeller shaft. Nautical propellers are often called screws. Rotating impellerblades increase the pressure difference between the inlet and outlet of a pump to force fluids through pipes. Turbines capture momentum from fast-moving fluid at high efficiency to a torque vector along the direction of the turbine's axis of rotation, while compressors use rotational motion to increase the pressure in a fast-moving fluid. Rotary fans move air, and can harness the reaction force of the moving air to drive a vehicle.
Calculation of forces acting on an object on an inclined plane
To calculate the forces on an object placed on an inclined plane, consider the three forces acting on it. Air resistance may be neglected for most calculations, except at high speeds.
normal force("N") exerted by the plane onto the body,
#the force due to gravity ("mg" - acting vertically downwards) and
#the frictional force ("f") acting parallel to the plane.
We can decompose the gravitational force into two vectors, one perpendicular to the plane and one parallel to the plane. Since there is no movement perpendicular to the plane, the component of the gravitational force in this direction ("mg"cos"θ") must be equal and opposite to normal force exerted by the plane, "N". If the remaining component of the gravitational force parallel to the surface ("mg"sin"θ") is greater than the
static frictional force "fs" - then the body will slide down the inclined plane with acceleration ("g"sin"θ" - fk/m), where fk is the kinetic frictionforce - otherwise it will remain stationary.
When the slope angle ("θ") is zero, sinθ is also zero so the body does not move.
* [http://www.phy.hk/wiki/englishhtm/Incline.htm An interactive simulation of Physics inclined plane]
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Look at other dictionaries:
Inclined plane — Inclined In*clined , p. p. & a. 1. Having a leaning or tendency towards, or away from, a thing; disposed or moved by wish, desire, or judgment; as, a man inclined to virtue. Each pensively inclined. Cowper. [1913 Webster] 2. (Math.) Making an… … The Collaborative International Dictionary of English
inclined plane — inclined′ plane′ n. mac one of the simple machines, a plane surface inclined to the horizon, or forming with a horizontal plane any angle but a right angle • Etymology: 1700–10 … From formal English to slang
inclined plane — ► NOUN ▪ a plane inclined at an angle to the horizontal, especially as a means of reducing the force needed to raise a load … English terms dictionary
inclined plane — n. a plane surface set at any angle other than a right angle against a horizontal surface: it is a simple machine that increases mechanical advantage but requires a longer working distance: See picture in next column … English World dictionary
inclined plane — 1. one of the simple machines, a plane surface inclined to the horizon, or forming with a horizontal plane any angle but a right angle. Cf. machine (def. 4b). 2. incline (def. 11a). [1700 10] * * * simple machine consisting of a sloping surface … Universalium
inclined plane — UK / US noun [countable] Word forms inclined plane : singular inclined plane plural inclined planes physics a flat surface that forms a slope, making an angle of less than 90 degrees with a horizontal surface … English dictionary
inclined plane — nuožulnioji plokštuma statusas T sritis fizika atitikmenys: angl. inclined plane vok. geneigte Ebene, f; schiefe Ebene, f rus. наклонная плоскость, f pranc. plan incliné, m … Fizikos terminų žodynas
inclined plane — /ɪnklaɪnd ˈpleɪn/ (say inkluynd playn) noun a plane surface inclined to the horizontal, or forming with a horizontal plane any angle but a right angle … Australian English dictionary
inclined plane — noun a plane inclined at an angle to the horizontal … English new terms dictionary
inclined plane — noun Date: 1710 a plane surface that makes an oblique angle with the plane of the horizon … New Collegiate Dictionary