The significance of the speed
The definition of speed
, n. Rate of motion. The terms SPEED and VELOCITY are often used interchangeably but SPEED is a scalar, having magnitude only while VELOCITY is a vector quantity, having both magnitude and direction. Rate of motion in a straight line is called linear speed, while change of direction per unit time is called angular velocity. Subsonic, sonic, and supersonic
refer to speeds respectively less than, equal to, greater than the speed of sound in standard air at sea level.
Transonic speeds are those in the range
in which flow
patterns change from subsonic to supersonic,
or vice versa.
Free English Dictionary:speed