In Virginia: Anthem Health Plans of Virginia, Inc. trades as Anthem Blue Cross and Blue Shield in Virginia, and its service area is all of Virginia except for the City of Fairfax, the Town of Vienna, and the area east of State Route 123.
For example, at sea level in a standard atmosphere, at a temperaturâ¦e of 59-degrees Fahrenheit (15 Celsius), sound travels 761 miles per hour (1,225 km/p/h). At a temperature of 32-degrees Fahrenheit (0 Celsius) the speed of sound drops to 742 mph (1,194 km/p/h).
In dry air at 20 Â°C (68 Â°F), the sound barrier is reached when an object moves at a speed of 343 metres per second (about 767 mph, 1234 km/h or 1,125 ft/s). The term came into use in this sense during World War II, when a number of aircraft started to encounter the effects of compressibility, a number of unrelated aerodynamic effects that struck their aircraft, seemingly impeding further acceleration.