*Power*

However, power is power. Either type of units could be used. It
would be -- and is -- entirely proper and correct to state that a
certain car has an engine which produces 98 kW (that is 132 hp).

As you can see from these graphics from a 19**83** Pontiac
brochure, General Motors has used SI (International System) units
internally for many, many years. Of course, that is true for all
other large US companies.

Like the engineers in other multi-national companies, GM's
engineers recorded data in SI units. Power is measured in kilowatts
(kW) and torque -- the rotational effect of a force -- is measured in
newton-meters (NM or N-m). This is not something new; remember these
graphics are from a 19**83** Pontiac brochure!

Here are excerpts from Francophone Canadian automobile brochures
that do, indeed, show the engine power in kilowatts (kW) **and**
in horsepower ("ch" for chavox in French).

James Watt patented the steam engine in 1769. To sell it, he
needed to tell people how many horses it would replace. Watt made the
first measurements on how much power a work horse could do -- he
measured how quickly farm horses could do work.

Watt was somewhat conservative in his marketing. There are few horses that
actually produce one horsepower of power.

Just as **WORK** is the **F**orce multiplied by the
**d**isplacement,

W** = F
d**

if we divide both sides by the amount of time involved we have that the Power
is equal to the Force multiplied by the **v**elocity,

P** = F
v**

**Return to ToC, Work and Kinetic Energy**
(C) 2005, Doug Davis; all rights reserved