Velocity(speed).
The speed of an object falling from a great height is measured in meters per second per second until it reaches terminal velocity (maximum downward speed).
meters per second
Because if speed is measured in meters per second (m/s) and time is measured in seconds, the SI unit of acceleration is meters per second per second (m/s2). ^_^
Meters per second
It is 300000000 metres per second, approx.
Meters per second
Acceleration is a change in speed, measured per second and so would be meters per second per second or meters per second squared.
Speed is distance divided by time. So : you could have meters per second, or meters per hour, etc.
You must show us those.
Speed or acceleration
It is about 9.814 meters per second per second on Earth
The SI unit for speed is meters per second.