Speed

To find out how fast something is moving we need to know TWO things about it:
(a) how far it has moved
(b) how long it took to move that distance
In other words a DISTANCE and a TIME.

SPEED = DISTANCE TRAVELLED/TIME TAKEN
or
DISTANCE TRAVELLED = SPEED x TIME TAKEN

Units for speed: metres per second (m/s), kilometres per hour (km/hr), miles per hour (mph).