Convert from nautical mile/hour to mach

Unit Definition (nautical mile/hour)
The knot is a unit of speed equal to one nautical mile per hour. Its kn abbreviation is preferred by American and Canadian maritime authorities, the Institute of Electrical and Electronics Engineers, and the International Bureau of Weights and Measures, however, the kt (knot) and kts (knots) abbreviations also are used. The knot is a non-SI unit accepted for use with the SI. World-wide, the knot is used in meteorology, and in maritime and aviation navigation — for example, a vessel travelling at 1 knot along a meridian, travels one-sixtieth of a degree of geographic latitude in one hour. Mariners first used the term knot denoting the measure of how many knots of line paid out in a given time using the chip log

Unit Definition (mach)
The Mach is a measure of velocity relative to the speed of sound. The precise speed of sound varies with the density and temperature of the atmosphere, although at 0 °C (at 1atm.) the speed of sound is 331.6 m/s. The mach speed is important to the control of an aircraft, especially at speeds close to or exceeding Mach 1.0. The unit is named after the Austrian physicist Ernst Mach.