Miles per hour (mph, mi/h)
Miles per hour (mph or mi/h) is a unit of speed. Mph is a unit commonly used to express the speed of vehicles, such as cars and trains in countries that have traditionally used the imperial system such as the United States and United Kingdom.
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.