"Mike Connor" wrote in message
...

"B J Conner" schrieb im Newsbeitrag
...

The most efficient humans don't even come close to 1 HP. Lance
Armstrong
and the guy who peddaled the Icarus project plane were 1/2 to 3/4 HP
peak
.
If I remember coorectly a man in good shape can crank out 125-150 watts.
Have you ever tried one of those bicycles that are connected to a
generator
driving a light bulb? They have ( or did have ) one at the science
museum
here. Trying to keep a 75 watt light bulb on is a killer.
IF Dr Sllishman gets 125 watt out of someone and keep him working 8 hrs
a
day he's got a kilowatt hour. Good for about 8.5 cents in Albuquerque.


Neither do horses. Horsepower was originally defined as about 746 watts,
based on the amount of work a horse can do in a day, not it´s output at
any
particular time.

The term horsepower was actually invented by the engineer James Watt. Watt
is most famous for his work on improving steam engines. Apparently, Watt
was working with pit-ponies lifting coal, and he needed to define the
power
available from these animals.

He discovered that a pit pony averaged about 22,000 foot-pounds of work in
a
minute. He increased this figure by fifty percent and set measurement of
horsepower at 33,000 foot-pounds of work per minute. This completely
arbitrary unit of measure is used to this day.

What you seem to be referring to, ( although one has to be careful here,
as
this is by no means always obvious) is the measure of the actual
mechanical
energy per unit time delivered to a turning shaft. 1 shaft horsepower = 1
electric horsepower = 550 ft-lb/second.

TL
MC

It doesn't have to be a turning shaft. If you can throw 55 ten pound
bricks over a 10 foot wall in one second your a one horsepower engine. Work
is force times distance, Power is the rate at which work is done. If
someone else throws the bricks over in 5 minutes samework, less power.
If I remember correctly ( which I seldom do) Watt used a unit of horse power
because mine owners used horses. If your selling steam engines to replace
horses it was handy to tell the customer that it would replace X horses.