reversed curves
51Permanent way — The permanent way means the physical elements of the railway line itself: generally the pairs of rails typically laid on sleepers embedded in ballast, intended to carry the ordinary trains of a railway. This page describes British practice and… …
52Contour line — This article is about lines of equal value in maps and diagrams. For more meanings of the word contour , see Contour (disambiguation). The bottom part of the diagram shows some contour lines with a straight line running through the location of… …
53Railway station layout — A railway station is a place where trains make scheduled stops. Stations usually have one or more platforms constructed alongside a line of railway. However, railway stations come in many different configurations influenced by such factors as the …
54Optical resolution — This article is about optical resolution in optics. For the method of separating enantiomers in chemistry, see Chiral resolution. Optical resolution describes the ability of an imaging system to resolve detail in the object that is being imaged.… …
55Line engraving — This article currently covers the history of line engraving until ca. 1910. Please extend it as needed, and remove this notice afterwards. Line engraving is a term for engraved images printed on paper to be used as prints or illustrations. The… …
56Magnetic field — This article is about a scientific description of the magnetic influence of an electric current or magnetic material. For the physics of magnetic materials, see magnetism. For information about objects that create magnetic fields, see magnet. For …
57Traffic light — The traffic light, also known as traffic signal, stop light, traffic lamp, stop and go lights, robot or semaphore, is a signaling device positioned at a road intersection, pedestrian crossing, or other location. Its purpose is to indicate, using… …
58Stepper motor — A stepper motor (or step motor) is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. The motor s position can be controlled precisely, without any feedback mechanism (see open loop control).… …
59Orbital mechanics — A satellite orbiting the earth has a tangential velocity and an inward acceleration. Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other… …
60Street football — s). Often the most basic of set ups will involve just a ball with a wall or fence used as a goal, or items such as clothing being used for goalposts (hence the phrase jumpers for goalposts ). The ease of playing these informal games means that… …
