Question: how many g forces is the speed of sound

title: Sound barrier
text: During WWII and immediately thereafter , a number of claims were made that the sound barrier had been broken in a dive . The majority of these purported events can be dismissed as instrumentation errors . The typical airspeed indicator ( ASI ) uses air pressure differences between two or more points on the aircraft , typically near the nose and at the side of the fuselage , to produce a speed figure . At high speed , the various compression effects that lead to the sound barrier also cause the ASI to go non-linear and produce inaccurately high or low readings , depending on the specifics of the installation . This effect became known as `` Mach jump '' . Before the introduction of Mach meters , accurate measurements of supersonic speeds could only be made externally , normally using ground - based instruments . Many claims of supersonic speeds were found to be far below this speed when measured in this fashion .