Technology and the Olympic Gold

[Charmed]

Dear Covers:

We use the unit called a horsepower (HP) to rate the power output (the energy delivered per second) of the modern automobile or aircraft engine, or an electric motor. It was James Watt conceived the idea of a horsepower when he tried to answer the question posed by his business partner Matthew Boulton (an attorney): How much work can your steam engine do? Back in the 18th century, horses were used to draw water out of the frequently flooded coal mines. Watt thought that his engine could replace the horse.

Of course, Watt came up with the answer and devised a method of comparing the work done by a horse and the work done by his engine. The rest is history. Boulton and Watt formed a company to market the new steam engine. They devised an ingenious marketing plan. The company would install the engines - for free. It would also service them - for free, for a period of five years. In return, they wanted the miners to pay them one-third of the difference between the cost of the hay needed to feed the horse(s) and the cost of the coal needed to run the engine. Watt had to find out how much hay a (well-fed) horse needs and how much "work" his engine could do. It was a well thought out business plan.

Now, what is the maximum HP the human body can produce? As I wondered about this (prompted by the obesity threads!), I came across this article.

(broken link removed)

What is the work done by a computer or an industrial robot? No one seems to have asked this question, or devised a method of measuring it, as far as I can tell. Any thoughts on this subject?

And, there are many other types of work - like the "work" must be done to boost the profits of a company, or the "work" that must be done to keep "defects" in the product to a minimum, and so on. Can we measure these types of "work" as well? I have been "bugged" by these questions for some time now.

Charmed

 

[Tim Folkerts]

Look Out! It's a physics lesson!:mg:

It's not too hard for a person to generate 1 hp for short periods of time. One simple way is to run up stairs.

1 HP = 550 ft*lb = 746 Watts
= lifting 550 lbs up 1 ft every second
= lifting 220 lbs up 2.5 ft every second
= lifting 110 lbs up 5 ft every second.

So if you are 220 lbs (100 kg) and can run up stairs at a rate of 2.5 ft (0.75 m) every second, you are producing 1 hp worth of power. If you are lighter, you have to go up faster to generate 1 HP.

In physics and engineering, "work" and "power" have very specific meanings in terms of forces, distances, and times. You could logically talk about the "work" done by a robot, but it isn't a very useful measure of what is happening. "work" in the physics meaning doen't really make sense when talking about people in offices or computers. (Although a resting person is metabolizing food at 50-100 W, so you are a 1/10 HP heater if you want to think of it that way!)

There are plenty of good ways to define "work" in a more useful form for other circumstances - # of calcuations done by a computer, or number of pieces made by a robot. "power" would then just be the rate at which this work was done.

Tim F

 

[Claes Gefvenberg]

If you are lighter, you have to go up faster to generate 1 HP.

Awwww. You're right. That's what I get for being in the featherweights division.

/Claes