Let's Look at the Speed Measured in Mach Value

Mach is a unit of measuring the speed of sound in a given medium; a plane traveling at .2 Mach moves at only two-tenths the speed of sound, while Mach 1 is equal to it. (The speed of sound is about 758 miles (1,220 kilometers) per hour at sea level, and decreases with altitude.) As [your moving object-maybe an air plane accelerates to Mach 1.06, controllers on the ground heard the first sonic boom. (The end of a bullwhip moves faster than the speed of sound. Some say the "crack" is a small sonic boom.)
It has been a long time since I studied this physics--Looking at it again gives it new meaning.

If you can't read the image it is: M=v/vsound

M is the Mach number,

v is the velocity of the source relative to the medium, and

vsound is the speed of sound in the medium.

From Wikipedia en,  Mach number varies by the composition of the surrounding medium and also by local conditions, especially temperature and pressure. A vapor cone is typically observed as an aircraft, or object, approaches transonic velocity.