What is 3400 kmph to mach speed?

Answer 1

The Mach number for the speed of an object travelling through a particular medium is the ratio of the object's speed relative to the speed of sound through the same medium. The speed of sound through any medium depends on the nature and density of the medium and, as a result, so does the Mach number. In air, the Mach ratio is mostly dependent on temperature and humidity and, to a lesser extent, on altitude.

Generally, Mach 1 (in air, at standard sea level conditions, and at 15 deg C) is approx 1223 kmph. So 3400 kmph would be approx 2.8 Mach. But 3400 kmph in water would be a very much lower Mach number.