Why is the speed of cars called "Horsepower"?

Answer 1

In the 1790's it was the power of one horse, as horses were used for transport. There have been many definitions for the term over the years since James Watt first coined the term in 1782, and there is no agreed amount of power for the term.The following metrics have been widely used:

Mechanical horsepower — 0.74569987158227022 kW (33,000 ft·lbs per minute)
Metric horsepower — 0.73549875 kW
Electrical horsepower — 0.746 kW
Boiler horsepower — 9.8095 kW
Additionally, the term "horsepower" has been applied to calculated (rather than measured) metrics

Answer 2

It isn't really, horsepower is a measurement of the pulling power of the engine. Obviously the more pulling power an engine has the faster it goes so the speed thing is a side effect if you like.

It's called horsepower because engines used to be measured against the other mode of transport of the day, the horse drawn carriage. If you connected a car with a 1 horsepower engine to a rope with a horse on the other end the tug-o-war would be a draw, a 2 horsepower engine would beat one horse but draw against 2 and so on.

Answer 3

Horsepower is a measure of work/time.

Wikipedia:
There have been many definitions for the term over the years since James Watt first coined the term in 1782. The following metrics have been widely used:

* Mechanical horsepower — 0.74569987158227022 kW (33,000 ft·lbs per minute)
* Metric horsepower — 0.73549875 kW
* Electrical horsepower — 0.746 kW
* Boiler horsepower — 9.8095 kW

Additionally, the term "horsepower" has been applied to calculated (rather than measured) metrics:

* RAC horsepower is based solely on the dimensions of a piston engine

That separates it from torque which is turning force. Horsepower can be calculated however by torque vs rpm.

Answer 4

Speed isnt called Horsepower. Horsepower relates to the power of the engine and not necessarily how fast it can go.

Answer 5

The power of an engine is commonly measured in "horsepower" this was done in times gone by when the "horseless carriage" as they were called first came about. The makers of these motorized carriages needed a way to tell people how powerful the engine was in terms that they could understand. Since everyone was familiar with horses and what they could pull, they used horse power.

Answer 6

It's not .Horsepower is power available to move a mass (car) eg
a car with more horsepower would accelerate faster than one which has less,as long as both cars are the same weight

Answer 7

It's not their speed but the power output of their engines. Originally, it was to compare with what people had been familiar with prior to engines being used. Then it became the basis for charging road tax ( where 125 c.c.equated with one horsepower). I see it expressed mostly now as Kw which I don't understand as I am so used to BHP as the measure.

Answer 8

Horsepower is a measurement of engine output not vehicle speed.

Answer 9

speed isn't horse power...horsepower is the amount of power the engine has..and its called that because the average work horse can do 745.6 Watts worth of work or 33,000ft/lbs of work a minute...so that is the amount of work that engine can do per minute so to speak...its just a measure of power...dont' worry about it...

Answer 10

It isn't

Horsepower refers to the power output of the engine. as in 200BHP. This has no reference to speed at all. Other factors effect speed, such as weight of vehicle and how aerodynamic it is. there are some new methods for working out power but the old HP or Brake Horse power was worked out as how fast you could lift a given weight over a certain vertical dist ace. It literally was how fast a horse could lift a given weight.