Current is measured in Amperes (usually just referred to as âAmpsâ). An ampere is defined as 6.241*10 18 electrons (1 Coulomb) per second passing through a point in a circuit. Amps are represented in equations by the letter âIâ.
The X-1, piloted by Chuck Yeager, was the first manned airplane to exceed the speed of sound in level flight and was the first of the X-planes, a series of American experimental rocket planes (and non-rocket planes) designated for testing of new technologies and often kept secret.
The speed of sound is not a constant, but depends on altitude (or actually the temperature at that altitude). A plane flying Mach 1.0 at sea level is flying about 1225 km/h (661 Knots, 761 mph), a plane flying Mach 1.0 at 30000 ft is flying 1091 km/h (589 knots, 678 mph) etc. Speeds below Mach 1 are called subsonic, between Mach 0.8-1.2 Transonic and above Mach 1.2 Supersonic. Â©1996-2011 Fighter Planes and Military Aircraft.