(distance off a desired course in either direction)
71Radar — For other uses, see Radar (disambiguation). A long range radar antenna, known as ALTAIR, used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on Kwajalein Atoll …
72mathematics — /math euh mat iks/, n. 1. (used with a sing. v.) the systematic treatment of magnitude, relationships between figures and forms, and relations between quantities expressed symbolically. 2. (used with a sing. or pl. v.) mathematical procedures,… …
73optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
74World War II — the war between the Axis and the Allies, beginning on September 1, 1939, with the German invasion of Poland and ending with the surrender of Germany on May 8, 1945, and of Japan on August 14, 1945. Abbr.: WWII * * * or Second World War (1939–45)… …
75hand tool — any tool or implement designed for manual operation. * * * Introduction any of the implements used by craftsmen in manual operations, such as chopping, chiseling, sawing, filing, or forging. Complementary tools, often needed as auxiliaries to… …
76Physical Sciences — ▪ 2009 Introduction Scientists discovered a new family of superconducting materials and obtained unique images of individual hydrogen atoms and of a multiple exoplanet system. Europe completed the Large Hadron Collider, and China and India took… …
77Latin America, history of — Introduction history of the region from the pre Columbian period and including colonization by the Spanish and Portuguese beginning in the 15th century, the 19th century wars of independence, and developments to the end of World War II.… …
78History of radar — The history of radar starts with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell s seminal work on electromagnetism.… …
79building construction — Techniques and industry involved in the assembly and erection of structures. Early humans built primarily for shelter, using simple methods. Building materials came from the land, and fabrication was dictated by the limits of the materials and… …
80motion-picture technology — Introduction the means for the production and showing of motion pictures. It includes not only the motion picture camera and projector but also such technologies as those involved in recording sound, in editing both picture and sound, in… …
