Mach vs. much
Mach
(a unit for measuring the speed by comparing it to the speed of sound)
- The aim was to fly at Mach 2, or twice the speed of sound.
- The maximum speed of this new type of fighter is Mach three. [Three times the speed of sound]
much
(a large amount; a large degree)
- It doesn’t cost much money.
- I’m feel much better today.