סליחה על השאלה המטומטמת: כמה כ"ס יש לסוס?

[עומרי]

(בהנחה שכוח של 1 כ"ס מרים 75 ק"ג לגובה של מטר בשנייה אחת). ובבקשה לא למחוק לי את ההודעה. איפה אני יכול לשאול כזאת שאלה אם לא פה???????

[חנן-ג'יפולוג]

כ"ס זה אומר להרים 75 ק"ג במהירות של מטר בשניה.

 

אז אם תיקח אדם במשקל של 75 ק"ג, האם הוא יכול לעלות במדרגות בקצב של מטר גובה בשניה? אני חושב שכן, ואפילו מהר יותר (מדובר בלעלות גובה של קומה אחת במדרגות במהלך שלוש שניות) . זה אומר שיש לו לפחות כ"ס אחד.

 

כמה כוחות סוס יש לסוס? לא יודע, אבל לפי האנלוגיה לאדם אני מניח שהרבה יותר מכ"ס אחד.

[sronis]

והנה ההסבר המדויק מתוך האו סטאף וורקס:

 

The story goes that Watt was working with ponies lifting coal at a coal mine, and he wanted a way to talk about the power available from one of these animals. He found that, on average, a mine pony could do 22,000 foot-pounds of work in a minute. He then increased that number by 50 percent and pegged the measurement of horsepower at 33,000 foot-pounds of work in one minute. It is that arbitrary unit of measure that has made its way down through the centuries and now appears on your car, your lawn mower, your chain saw and even in some cases your vacuum cleaner!

 

What horsepower means is this: In Watt's judgement, one horse can do 33,000 foot-pounds of work every minute. So, imagine a horse raising coal out of a coal mine as shown above. A horse exerting 1 horsepower can raise 330 pounds of coal 100 feet in a minute, or 33 pounds of coal 1,000 feet in one minute, or 1,000 pounds 33 feet in one minute. You can make up whatever combination of feet and pounds you like. As long as the product is 33,000 foot-pounds in one minute, you have a horsepower.

 

You can probably imagine that you would not want to load 33,000 pounds of coal in the bucket and ask the horse to move it 1 foot in a minute because the horse couldn't budge that big a load. You can probably also imagine that you would not want to put 1 pound of coal in the bucket and ask the horse to run 33,000 feet in one minute, since that translates into 375 miles per hour and horses can't run that fast. However, if you have read How a Block and Tackle Works, you know that with a block and tackle you can easily trade perceived weight for distance using an arrangement of pulleys. So you could create a block and tackle system that puts a comfortable amount of weight on the horse at a comfortable speed no matter how much weight is actually in the bucket.

 

רוני