Speed
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In everyday use and in kinematics, the speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is the magnitude of velocity, which indicates additionally the direction of motion.
Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a given amount of time, while a slow-moving object covers a relatively small amount of distance in the same amount of time.
Boeing 747-8
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The Boeing 747-8 is the final series of the large, long-range wide-body airliners in the Boeing 747 family from Boeing Commercial Airplanes. The 747-8 is the largest variant of the 747 and Boeing's largest aircraft.
After introducing the 747-400, Boeing considered larger 747 versions as alternatives to the proposed double-deck Airbus A3XX, later developed as the Airbus A380.
The stretched 747 Advanced was launched as the 747-8 on November 14, 2005, for a market forecast of 300 aircraft.
The first 747-8F Freighter performed its maiden flight on February 8, 2010, and the passenger 747-8I Intercontinental followed suit on March 20, 2011.
The cargo version was first delivered in October 2011 and the airliner began commercial service in June 2012.
Boeing 747-400 and 747-500X concept. The 747-500X fuselage would have been stretched by 18 ft (5.5 m) to 250 ft (76.2 m) long. The 747X and 747X Stretch derivatives were also proposed.
Boeing's Everett Facility at Paine Field, originally built for the 747 program, is the site of 747-8 assembly.
The 747-8 landing gear configuration is the same as on earlier 747 versions.