speed measurement
51wind chill temperature index — (WCTI) a measurement of the combined cooling effect of low air temperature and wind on the human body. The index was first defined by the American Antarctic explorer Paul Siple in 1939. As originally used by U.S. meteorologists, the wind chill …
52degree — 1. (° or deg) the standard unit of angle measure, equal to 1/360 circle, 60 minutes, 3600 seconds, or about 0.017 453 293 radian. So far as we know, this unit was introduced by the Greek geometer Hipparchus of Nicaea (ca. 180 ca. 125 BC),… …
53× — 1. or x or X the usual symbol for power as a unit of magnification. More generally, × or x is used with its mathematical meaning, times, to indicate that a measurement is a multiple of some standard or reference measurement. For example, an …
54c — 1. see cycle 2. see cup 3. see carat 4. a symbol for the speed of light. One of the fundamental principles of physics is that light always travels at the same speed ina vacuum, exactly 299 792 458 meters per second or about 670 617… …
55ton — 1. (tn or T or t) a traditional unit of weight equal to 20 hundredweight. In the United States and Canada, there are 100 pounds in the hundredweight and exactly 2000 pounds (907.185 kilograms) in the ton. In Britain, there are 112 pounds …
56Beaufort scale — an empirical scale, first devised by the British admiral Sir Francis Beaufort (1774 1857), for estimating wind speed by observing the effects of the wind. Using the scale, sailors can judge the wind velocity by observing the wind s effects on… …
57power (x) — 1. a unit expressing the magnifying power of an optical system. The power is defined to be the angular diameter of the image formed by the system divided by the angular diameter of the original object being observed. In simple telescopes this… …
58ASA number — for many years, the initials of the American Standards Association appeared on film packages in the United States as a measure of the speed of the photographic emulsion (the stuff on the film that develops to form the picture). The scale is… …
59DIN — the initials of Deutsches Institut für Normung, the German standards agency. Outside the U.S., film was generally marked with a DIN speed rating such as DIN 24 (corresponding to ASA 200). A difference of 3 in the DIN rating corresponds to a… …
60gear inch — a traditional unit for measuring the gears of bicycles. In low gears, the pedals are easy to turn but have to be turned very fast to achieve any speed; in high gears the pedals are harder to turn but don t have to be turned fast to achieve… …
