The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). This is 1,236 kilometres per hour (768 mph), or about one kilometer in three seconds or approximately one mile in five seconds.

In fluid dynamics, the speed of sound in a fluid medium (gas or liquid) is used as a relative measure of speed itself. The speed of an object (in distance per time) divided by the speed of sound in the fluid is called the Mach number. Objects moving at speeds greater than Mach1 are traveling at supersonic speeds.

The speed of sound in an ideal gas is independent of frequency, but it weakly depends on frequency for all real physical situations. It is a function of the square root of the absolute temperature, but is nearly independent of pressure or density for a given gas. For different gases, the speed of sound is inversely dependent on square root of the mean molecular weight of the gas, and affected to a lesser extent by the number of ways in which the molecules of the gas can store heat from compression, since sound in gases is a type of compression. Although, in the case of gases only, the speed of sound may be expressed in terms of a ratio of both density and pressure, these quantities are not fully independent of each other, and canceling their common contributions from physical conditions leads to a velocity expression using the independent variables of temperature, composition, and heat capacity noted above.

Aaron Dontez Yates (born November 8, 1971), better known by his stage name Tech N9ne (pronounced "Tech Nine"), is an American rapper from Kansas City, Missouri. In 1999, Yates and Travis O'Guin founded the record label Strange Music. Throughout his career, Yates has sold over one million albums and has had his music featured in film, television, and video games. In 2009, he won the Left Field Woodie award at the mtvU Woodie Awards.

His stage name originated from the TEC-9 semi-automatic handgun, given to him by rapper Black Walt due to his fast rhyming style. Yates later applied a deeper meaning to the name, claiming that it stands for the complete technique of rhyme, with 'tech' meaning technique and 'nine' representing the number of completion.

Aaron Dontez Yates was born on November 8, 1971 in Kansas City, Missouri. He began rapping at a very early age, and would rap the letters of his name in order to remember how to spell it. He never met his father, and his mother suffered from epilepsy and lupus when he was a child, which emotionally affected him and inspired him to "search for God." He would wander around abandoned buildings with his best friend, Brian Dennis, hoping to catch a ghost on film. In 2003, Dennis was shot and killed by his girlfriend's ex-boyfriend, which further inspired Yates' search for a higher power, as well as giving him the drive to vent his frustrations in his music.