Basically, you can divide any unit of length by any unit of time. The standard SI unit is meters/second, but kilometers/hour are also commonly used worldwide. In the United States, miles/hour are used instead; but it is possible to use any unit of distance, divided by any unit of time, e.g. meters/minute, millimeters/year, parsecs / million years, astronomical units / month. (The slash, /, is usually read as "per" in English.)
There are also specific units that don't directly derived from distance and time, such as knots, or (in the natural system of units), the speed of an object compared to the speed of light.
what are the four units of speed
For a start, acceleration doesn't even have the same units as velocity: acceleration is a velocity divided by time, so while speed or velocity have units of [distance]/[time], acceleration has units of [distance]/[time squared]
Velocity is speed and its direction. The units of velocity are any unit of speed and any means of indicating a direction.
units of speed = units of distance/units of time Examples: miles per hour (mi/hr), meters per second (m/s), kilometers per hour (km/hr).
radians/second
No. Speed, time, and energy are three quite different units.No. Speed, time, and energy are three quite different units.No. Speed, time, and energy are three quite different units.No. Speed, time, and energy are three quite different units.
what are the four units of speed
Variable speed drivers are necessary to be able to have different speed settings in a motor.
You can not convert between units of time and units of length - they measure completely different things. If it is a speed problem, you must know ore assume the speed, then divide the number of miles by the speed.
I am not at all sure what you mean; you might use four different speed units for example.
the units for rotational speed are radians / sec or degrees / sec
because they measure different aspects of the same thing, velocity also has direction but speed lacks direction. otherwise they are the same.
Miles per hour Kilometer per hour Ft per sec
That depends on what you're trying to measure. Volume, weight, speed, etc. all have different units of measurement.
I have no idea what you mean with "functional unit". The SI has units to measure lots of different things; basically there are seven base units (such as the meter, the second, and the kilogram), and several dozen derived units, i.e., units derived from the base units, for example meters/second for speed.
For a start, acceleration doesn't even have the same units as velocity: acceleration is a velocity divided by time, so while speed or velocity have units of [distance]/[time], acceleration has units of [distance]/[time squared]
No. Measurement units are defined by and conversely. So the same units necessarily means same dimensions.