different units of measuring speed
Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour. For air and marine travel the knot is commonly used.
Units of speed include: 1  metres per second (symbol m sâ1 or m/s), the SI derived unit; 2  kilometres per hour (symbol km/h); 3  miles per hour (symbol mi/h or mph); 4  knots (nautical miles per hour, symbol kn or kt);  feet per second (symbol fps or ft/ 1 s); Mach number (dimensionless), speed divided by the speed of sound;