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In late afternoon, a supersonic American Air Force jet streaks across the Sky, capable of flying at several times the speed of sound. Inside the F-16, a bearded pilot sees his plane disintegrate as its speed increases from Mach 1, Mach 2… Suddenly… Mach 3… Wow!!!!!! The pilot appears clean shaven, with a Gillette razor in hand. A new model, known as Mach 3, with three blades that shave closer and much faster* (Click here to see a video).
Speed of sound
In the 19th century the Austrian physicist and philosopher Ernest Mach studied the action of bodies that travel at high speeds and how to measure them precisely. He also studied shock waves and how to break the speed of sound. The Mach unit (Ma) was created in his honor and is defined as the relationship between the velocity of the object and the speed of sound.
Thus, when a body reaches the speed of sound, approximately 1,224 Km/h**, its Mach is 1 (sonic speed). A body reaches Mach 3 when its velocity is 3×1.224, that is, approximately 3,672 Km/h (supersonic speed). For Ma > 5, the speeds are known as hypersonic.
What is the sound barrier?
An increase in speed accumulates shock waves in front of the body, when its speed is close to that of the spreading of these waves. A “compressed air barrier” emerges at the front of the body. When the body exceeds the speed of sound, it literally breaks this barrier (Click here) and a very strong boom is heard.
* Manufacturer’s information ** Speed varies with temperature and local air pressure.
Recommended visting:
http://en.wikipedia.org/wiki/Ernst_Mach
http://pt.wikipedia.org/wiki/N%C3%BAmero_de_Mach
Author: Pedro de Lemos Menezes
Email: pedrodelemosmenezes@gmail.com
Posts: Every friday.
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