Meters per second (m/s)
Meters per second (m/s) is the SI unit of speed or velocity. It represents the distance traveled in meters over one second.
It is used mainly in physics and engineering from describing the speed of a moving vehicle to the velocity of an object in free fall. It's simplicity makes it a good choice for describing speed and comparison with other units of speed.
Knots
A Knot is a unit to measure speed. A knot is equal to one nautical mile per hour. Normally this unit is used in maritime and aviation.