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Inclined Plane
An inclined plane, also known as a ramp, is a flat supporting surface tilted at an angle from the vertical direction, with one end higher than the other, used as an aid for raising or lowering a load. The inclined plane is one of the six classical simple machines defined by Renaissance scientists. Inclined planes are used to move heavy loads over vertical obstacles. Examples vary from a ramp used to load goods into a truck, to a person walking up a pedestrian ramp, to an automobile or railroad train climbing a grade. Moving an object up an inclined plane requires less force than lifting it straight up, at a cost of an increase in the distance moved. The mechanical advantage of an inclined plane, the factor by which the force is reduced, is equal to the ratio of the length of the sloped surface to the height it spans. Owing to conservation of energy, the same amount of mechanical energy ( work) is required to lift a given object by a given vertical distance, disregarding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cylinder (geometry)
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite curvilinear surface in various modern branches of geometry and topology. The shift in the basic meaning—solid versus surface (as in ball and sphere)—has created some ambiguity with terminology. The two concepts may be distinguished by referring to solid cylinders and cylindrical surfaces. In the literature the unadorned term cylinder could refer to either of these or to an even more specialized object, the ''right circular cylinder''. Types The definitions and results in this section are taken from the 1913 text ''Plane and Solid Geometry'' by George Wentworth and David Eugene Smith . A ' is a surface consisting of all the points on all the lines which are parallel to a given line and which pass through a fixed plane curve in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Causeway
A causeway is a track, road or railway on the upper point of an embankment across "a low, or wet place, or piece of water". It can be constructed of earth, masonry, wood, or concrete. One of the earliest known wooden causeways is the Sweet Track in the Somerset Levels, England, which dates from the Neolithic age. Timber causeways may also be described as both boardwalks and bridges. Etymology When first used, the word ''causeway'' appeared in a form such as "causey way" making clear its derivation from the earlier form "causey". This word seems to have come from the same source by two different routes. It derives ultimately, from the Latin for heel, ''calx'', and most likely comes from the trampling technique to consolidate earthworks. Originally, the construction of a causeway utilised earth that had been trodden upon to compact and harden it as much as possible, one layer at a time, often by enslaved bodies or flocks of sheep. Today, this work is done by machines. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evacuation Slide
An evacuation slide is an inflatable slide used to evacuate an aircraft quickly. An escape slide is required on all commercial (passenger carrying) aircraft where the door sill height is such that, in the event of an evacuation, passengers would be unable to step down from the door uninjured (Federal Aviation Administration requires slides on all aircraft doors where the floor is or more above the ground). Escape slides are packed and held within the door structure inside the ''slide bustle'', a protruding part of the inside of an aircraft door that varies with aircraft size, door size and door location. In many modern planes, to reduce evacuation time, evacuation slides deploy automatically when a door is opened in an "armed" condition. Modern planes often indicate an armed condition with an indicator light. Regulations Federal Aviation Administration and EASA regulations require an approved method of escape on all aircraft exits where the floor is or more above the ground ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airliner
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an airplane intended for carrying multiple passengers or cargo in commercial service. The largest of them are wide-body jets which are also called twin-aisle because they generally have two separate aisles running from the front to the back of the passenger cabin. These are usually used for long-haul flights between airline hubs and major cities. A smaller, more common class of airliners is the narrow-body or single-aisle. These are generally used for short to medium-distance flights with fewer passengers than their wide-body counterparts. Regional airliners typically seat fewer than 100 passengers and may be powered by turbofans or turboprops. These airliners are the non- mainline counterparts to the larger aircraft operated by the major c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evacuation Slide
An evacuation slide is an inflatable slide used to evacuate an aircraft quickly. An escape slide is required on all commercial (passenger carrying) aircraft where the door sill height is such that, in the event of an evacuation, passengers would be unable to step down from the door uninjured (Federal Aviation Administration requires slides on all aircraft doors where the floor is or more above the ground). Escape slides are packed and held within the door structure inside the ''slide bustle'', a protruding part of the inside of an aircraft door that varies with aircraft size, door size and door location. In many modern planes, to reduce evacuation time, evacuation slides deploy automatically when a door is opened in an "armed" condition. Modern planes often indicate an armed condition with an indicator light. Regulations Federal Aviation Administration and EASA regulations require an approved method of escape on all aircraft exits where the floor is or more above the ground ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Force
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force and 1029 times weaker than the weak interaction. As a result, it has no significant influence at the level of subatomic particles. However, gravity is the most significant interaction between objects at the macroscopic scale, and it determines the motion of planets, stars, galaxies, and even light. On Earth, gravity gives weight to physical objects, and the Moon's gravity is responsible for sublunar tides in the oceans (the corresponding antipodal tide is caused by the inertia of the Earth and Moon orbiting one another). Gravity also has many important biological functions, helping to guide the growth of plants through the process of gravitropism and influencing the circul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Force
In mechanics, the normal force F_n is the component of a contact force that is perpendicular to the surface that an object contacts, as in Figure 1. In this instance '' normal'' is used in the geometric sense and means perpendicular, as opposed to the common language use of ''normal'' meaning "ordinary" or "expected". A person standing still on a platform is acted upon by gravity, which would pull them down towards the Earth's core unless there were a countervailing force from the resistance of the platform's molecules, a force which is named the "normal force". The normal force is one type of ground reaction force. If the person stands on a slope and does not sink into the ground or slide downhill, the total ground reaction force can be divided into two components: a normal force perpendicular to the ground and a frictional force parallel to the ground. In another common situation, if an object hits a surface with some speed, and the surface can withstand the impact, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conveyor Belt
A conveyor belt is the carrying medium of a belt conveyor system (often shortened to belt conveyor). A belt conveyor system is one of many types of conveyor systems. A belt conveyor system consists of two or more pulleys (sometimes referred to as drums), with a closed loop of carrying medium—the conveyor belt—that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the idler pulley. There are two main industrial classes of belt conveyors; Those in general material handling such as those moving boxes along inside a factory and bulk material handling such as those used to transport large volumes of resources and agricultural materials, such as grain, salt, coal, ore, sand, overburden and more. Overview Conveyors are durable and reliable components used in automated distribution and warehousing, as well as manufacturing and pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escalator
An escalator is a moving staircase which carries people between floors of a building or structure. It consists of a motor-driven chain of individually linked steps on a track which cycle on a pair of tracks which keep the step tread horizontal. Escalators are often used around the world in places where lifts would be impractical, or they can be used in conjunction with them. Principal areas of usage include department stores, shopping malls, airports, transit systems (railway/railroad stations), convention centers, hotels, arenas, stadiums and public buildings. Escalators have the capacity to move large numbers of people. They have no waiting interval (except during very heavy traffic). They can be used to guide people toward main exits or special exhibits and may be weatherproofed for outdoor use. A non-functional escalator can function as a normal staircase, whereas many other methods of transport become useless when they break down or lose power. Design, components, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheelchair
A wheelchair is a chair with wheels, used when walking is difficult or impossible due to illness, injury, problems related to old age, or disability. These can include spinal cord injuries ( paraplegia, hemiplegia, and quadriplegia), cerebral palsy, brain injury, osteogenesis imperfecta, motor neurone disease, multiple sclerosis, muscular dystrophy, spina bifida, and more. Wheelchairs come in a wide variety of formats to meet the specific needs of their users. They may include specialized seating adaptions, individualized controls, and may be specific to particular activities, as seen with sports wheelchairs and beach wheelchairs. The most widely recognized distinction is between motorized wheelchairs, where propulsion is provided by batteries and electric motors, and manual wheelchairs, where the propulsive force is provided either by the wheelchair user or occupant pushing the wheelchair by hand ("self-propelled"), by an attendant pushing from the rear using t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheelchair Ramp
A wheelchair ramp is an inclined plane installed in addition to or instead of stairs. Ramps permit wheelchair users, as well as people pushing strollers, carts, or other wheeled objects, to more easily access a building, or navigate between areas of different height. Ramps for accessibility may predate the wheelchair and are found in ancient Greece. A wheelchair ramp can be permanent, semi-permanent or portable. Permanent ramps are designed to be bolted or otherwise attached in place. Semi-permanent ramps rest on top of the ground or concrete pad and are commonly used for the short term. Permanent and semi-permanent ramps are usually of aluminum, concrete or wood. Portable ramps are usually aluminum and typically fold for ease of transport. Portable ramps are primarily intended for home and building use but can also be used with vans to load an unoccupied mobility device or to load an occupied mobility device when both the device and the passenger are easy to handle. Ramps mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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