Understanding Speed: From MPH to Mach

Speed is a familiar concept, but its measurement varies wildly across different fields.

Specialized Units: Knots and Mach

Knot (kn): The standard for speed in aviation and maritime. One knot is one nautical mile per hour. It's used because it ties directly to the Earth's coordinates (latitude/longitude), making navigation easier.

Mach (M): A ratio of an object's speed to the speed of sound. Mach 2 is twice the speed of sound. The actual speed of Mach 1 changes with temperature and altitude.

Speed vs. Velocity

In physics, they are different. Speed is how fast you are going (e.g., 60 mph). Velocity is how fast you are going *and in what direction* (e.g., 60 mph North).