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Ground Pressure
Ground pressure is the pressure exerted on the ground by the tires or tracks of a motorized vehicle, and is one measure of its potential mobility, especially over soft ground. It also applies to the feet of a walking person or machine. Pressure is measured in the SI unit of pascals (Pa). Average ground pressure can be calculated using the standard formula for average pressure: ''P'' = ''F''/''A''. In an idealised case, i.e. a static, uniform net force normal to level ground, this is simply the object's weight divided by contact area. The ground pressure of motorized vehicles is often compared with the ground pressure of a human foot, which can be 60 – 80 kPa while walking or as much as 13 MPa for a person in spike heels. Increasing the size of the contact area on the ground (the ''footprint'') in relation to the weight decreases the unit ground pressure. Ground pressure of 14 kPa (2 psi) or less is recommended for fragile ecosystems like marshes. Decreasing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various #Units, units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the International System of Units, SI unit of pressure, the Pascal (unit), pascal (Pa), for example, is one newton (unit), newton per square metre (N/m2); similarly, the Pound (force), pound-force per square inch (Pound per square inch, psi, symbol lbf/in2) is the traditional unit of pressure in the imperial units, imperial and United States customary units, US customary systems. Pressure ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toyota 4Runner
The Toyota 4Runner is an SUV manufactured by the Japanese automaker Toyota and marketed globally since 1984, across six generations. In Japan, it was marketed as the and was withdrawn from the market in 2009. The original 4Runner was a compact SUV and little more than a Toyota Hilux pickup truck with a fiberglass shell over the bed, but the model has since undergone significant independent development into a cross between a compact and a mid-size SUV. All 4Runners have been built in Japan at Toyota's plant in Tahara, Aichi, or at the Hino Motors (a Toyota subsidiary) plant in Hamura. The name "4Runner" was created by copywriter Robert Nathan with the Saatchi & Saatchi advertising company as a play on the term "forerunner". The agency held contests to invent new names for Toyota's forthcoming vehicles. According to Toyota, the "4" described the vehicle's 4-wheel drive system while "Runner" was a reference to its all-terrain capabilities and how it could "run" off-road. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tire Load Sensitivity
Tire load sensitivity describes the behaviour of tires under load. Conventional pneumatic tires do not behave as classical friction theory would suggest. The load sensitivity of most real tires in their typical operating range is such that the coefficient of friction decreases as the vertical load, Fz, increases. The maximum lateral force that can be developed does increase as the vertical load increases, but at a diminishing rate. Behaviour Coulomb friction theory says that the maximum horizontal force developed should be proportional to the vertical load on the tire. In practice, the maximum horizontal force Fy that can be generated is proportional, roughly, to the vertical load Fz raised to the power of somewhere between 0.7 and 0.9, typically. Production car tires typically develop this maximum lateral force, or cornering force, at a slip angle of 6-10 degrees, although this angle increases as the vertical load on the tire increases. Formula 1 car tires may reach a peak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Patch
The contact patch is the portion of a vehicle's tire that is in actual contact with the road surface. It is commonly used in the discussion of pneumatic (i.e. pressurized) tires, where the term is used strictly to describe the portion of the tire's tread that touches the road surface. The term “footprint” is used almost synonymously. Solid wheels also exhibit a contact patch which is generally smaller than the pneumatic “footprint”. Contact patch size The contact patch is the only connection between the road and the vehicle. Pneumatic rubber tires The size and shape of the contact patch, as well as the pressure distribution within the contact patch, are important to the ride qualities and handling characteristics of a vehicle. Since the wear characteristics of tires is a highly competitive area between tire manufacturers, a lot of the research done concerning the contact patch is considered highly proprietary and, therefore, very little is published on the subject. Be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tire
A tire (North American English) or tyre (Commonwealth English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, providing a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, designed to match the vehicle's weight and the bearing on the surface that it rolls over by exerting a pressure that will avoid deforming the surface. The materials of modern pneumatic tires are synthetic rubber, natural rubber, fabric, and wire, along with carbon black and other chemical compounds. They consist of a tire tread, tread and a body. The tread provides Traction (engineering), traction while the body provides containment for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stiletto Heel
A stiletto heel, or just stiletto, is a shoe with a long, thin, high heel. It is named after the stiletto dagger. Stiletto heels may vary in length from 2.5 centimetres (1 inch) to 25 cm (10 inches) or more if a platform sole is used, and are sometimes defined as having a diameter at the ground of less than 1 cm (slightly less than half an inch). Stiletto-style heels or shorter are called kitten heels. History High-heeled shoes were worn by men and women courtiers until the French Revolution. When high heels came back in style in the late 1800s, they were worn only by women. The stiletto heel came with the advent of technology using a supporting metal shaft or stem embedded into the heel, instead of wood or other, weaker materials that required a wide heel. Italian shoe designer Salvatore Ferragamo paved the way for stilettos by inventing the steel arch. Some historians also credit him with inventing the stiletto heel, while others credit French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Racing Bicycle
A racing bicycle, also known as a road bike, is a bicycle designed for competitive road cycling, a sport governed by and according to the rules of the Union Cycliste Internationale (UCI). Racing bicycles are designed for maximum performance while remaining legal under the UCI rules. They are designed to minimise aerodynamic drag, rolling resistance, and weight, and balance the desire for stiffness for pedaling effiency with the need for some flexibility for comfort. Racing bicycles sacrifice comfort for speed compared to non-racing bicycles. The drop handlebars are positioned lower than the saddle to put the rider in a more aerodynamic posture. The front and back wheels are close together so the bicycle has quick handling, which is preferred by experienced racing cyclists. The derailleur gear ratios are closely spaced so that the rider can pedal at their optimum cadence. However, racing bicycles must retain the ability to maneuver safely within a tightly-packed peloton, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountain Bike
A mountain bike (MTB) or mountain bicycle is a bicycle designed for off-road cycling (''mountain biking''). Mountain bikes share some similarities with other bicycles, but incorporate features designed to enhance durability and performance in rough terrain, which often makes them heavier, more complex and less efficient on smooth surfaces. These typically include a bicycle fork, suspension fork, large knobby tires, more durable Bicycle wheel, wheels, more powerful brakes, straight, wide handlebars to improve balance and comfort over rough terrain, and wide-ratio gearing optimized for topography, application (e.g., steep climbing or fast descending) and a frame with a bicycle suspension, suspension mechanism for the rear wheel. Rear suspension is ubiquitous in heavier-duty bikes and now common even in lighter bikes. Dropper seat posts can be installed to allow the rider to quickly adjust the seat height (an elevated seat position is more effective for pedaling, but poses a hazard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elephant
Elephants are the largest living land animals. Three living species are currently recognised: the African bush elephant ('' Loxodonta africana''), the African forest elephant (''L. cyclotis''), and the Asian elephant ('' Elephas maximus''). They are the only surviving members of the family Elephantidae and the order Proboscidea; extinct relatives include mammoths and mastodons. Distinctive features of elephants include a long proboscis called a trunk, tusks, large ear flaps, pillar-like legs, and tough but sensitive grey skin. The trunk is prehensile, bringing food and water to the mouth and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears and convex or level backs. Elephants are scatter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bagger 288
Bagger 288 (Excavator 288), previously known as the MAN TAKRAF RB288 built by the German company Krupp for the energy and mining firm Rheinbraun, is a bucket-wheel excavator or mobile strip mining machine. When its construction was completed in 1978, Bagger 288 superseded Big Muskie as the heaviest land vehicle in the world, at 13,500 tons. It took five years to design and manufacture and five years to assemble, with total cost reaching $100 million. In 1995, it was itself superseded by the slightly heavier Bagger 293 (14,200 tons). XCMG's XGC88000 Crawler Crane remains the largest self-propelled land vehicle in the world, since bucket-wheel excavators are powered by an external power source, and the Overburden Conveyor Bridge F60s hold the title of largest land vehicle of any type by physical dimensions. Like its siblings, the Bagger 288 require a disproportionately small number of people to operate, at just five total. Whilst Bagger 288 is considered a "sibling vehicle" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (mass)
The pound or pound-mass is a unit of mass used in both the British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly , and which is divided into 16 avoirdupois ounces. The international standard symbol for the avoirdupois pound is lb; an alternative symbol (when there might otherwise be a risk of confusion with the pound-force) is lbm (for most pound definitions), # ( chiefly in the U.S.), and or ̶ (specifically for the apothecaries' pound). The unit is descended from the Roman (hence the symbol ''lb'', descended from the scribal abbreviation, '). The English word ''pound'' comes from the Roman ('the weight measured in '), and is cognate with, among others, German , Dutch , and Swedish . These units are now designated as historical and are no longer in common usage, being replaced by the metric system. Usage of the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, '' Eohippus'', into the large, single-toed animal of today. Humans began domesticating horses around 4000 BCE in Central Asia, and their domestication is believed to have been widespread by 3000 BCE. Horses in the subspecies ''caballus'' are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, which are horses that have never been domesticated. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior. Horses are adapted to run, allowing them to quickly escape predator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
