US Standard Speed (Velocity)
These are the most common measurements::
 Feet per Second (fps)
 Miles per Hours (mph)

Speed
Speed in feet per second (fps)
This is a combination of two units (feet and seconds) to make a new one (fps).
If something is traveling at 1 fps it moves 1 foot every second.
Speed in miles per hour (mph)
A bit more complicated, but a mile has 5,280 feet, and an hour has 3,600 seconds, so a mile per hour is:
 5280 / 3600 = 1.467 fps (to 3 decimal places)
How did I know to make it 5280/3600, and not 3600/5280 (the other way around)? Read how to Safely Convert From One Unit to Another.
Velocity
Velocity is speed with a direction.
So if something is moving at 5 mph that is a speed.
But if you say it is moving at 5 mph westwards that is a velocity.
If something moves backwards and forwards very fast it has a high speed, but a low (or zero) velocity
More Examples
60 mph is about:
 how fast you can legally go on a highway
 the maximum running speed of a cheetah
 the speed needed to drive one mile in a minute
 half the freefall speed of a skydiver
35 mph is about:
 the speed limit in the city
 going very fast on a bicycle
 the speed of a racehorse on a short track
 full running speed of a Bengal Tiger
1 foot per second is:
 exactly 0.3048 metres per second
 approximately 0.6818 miles per hour
 exactly 1.09728 km per hour
