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jared2

Published Letters: 453
Editor's Choice: 16

Tuesday, January 9, 2007 07:55 AM
Original article: Ask the pilot

Treadmill speed does not equal groundspeed

"The condition in the question that "the wheels and the treadmill move at the same speed" is intended to imply that the plane's ground speed is zero"

I disagree. I think this condition, "the wheels and the treadmill move at the same speed" is intended to show that the plane's wheels do not drive the plane, but simply turn freely under the treadmill. The wheels of the plane will be driven by:

1. The friction with the treadmill, and

2. The forward motion of the plane as it takes off

As the plane begins its takeoff roll, the treadmill will speed up to match the tire speed (the premise of the question requires this) The plane will accelerate down the runway normally, as it is driven by engine thrust, not tire traction. The plane will also have normal groundspeed as it moves down the runway. The tires will not burn rubber, as the treadmill exactly matches the tire speed. The plane will, in fact, have a completely normal takeoff to any observer on the plane or on the ground. It will proceed down the runway, reach normal airspeed and normal groundspeed and take off. The treadmill is simply irrelevant.

Tuesday, January 9, 2007 11:15 AM
Original article: Ask the pilot

Re: Ridiculous

It is not necessarily ridiculous, though obviously impractical. Imagine the plane is at the start of the runway/treadmill. Imagine the treadmill is computer-controlled to exactly match the speed of the plane's wheels. The plane slowly begins to move forward as the pilot applies power. As the plane begins to move down the runway, the treadmill, moves in the opposite direction and at the same speed as the wheels. The Wheels rotate clockwise if we look at the plane from the right side; the treadmill moves backward. The plane will move down the runway normally, due to the force of the engines on the air. The airspeed and groundspeed will build up normally. The wheels will still be turning in syncrony with the treadmill, but this has no effect on the forward motion of the plane which is due to aerodynamic thrust. The plane will move down the runway - it will not remain still, as a car would on a treadmill. It will look exactly like a normal takeoff. The fact that the treamill is turning under the wheels is irrelevant.

Wednesday, January 10, 2007 08:03 AM

"what papers out there are worth reading any more?"

The Guardian, for a start. The NY Times is not bad. As for reading them in 20 minutes - that is for poseurs. Just try reading the Sunday New York Times in under 2 hours. As someone who reads a great deal of both print and online material (at least 6 hours a day), print is much, much easier on the eyes an always will be. (Sorry, trees)

Thursday, January 11, 2007 08:25 AM

A lack of common sense is to blame

Kim's death has little to do with a lack of awareness of wilderness areas and eveything to do with a lack of common sense. Highly trained professionals may also lack this. The captain of the Titanic steamed full speed into a area known to be likely to contain icebergs. Had he just slowed down, the ship would have either not hit an iceberg, or hit one lightly enough to suffer no hull damage. All Kim had to do was make a u-turn back to a major highway as soon as he knew he was lost. Pressing on into increasingly narrow and bad roads violates every notion of common sense.

Friday, January 12, 2007 07:38 AM
Original article: Ask the pilot

Treadmill question

Odd. I found the treadmill question one of the more interesting columns. It made me think, and that is, I suppose, the clue to its unpopularity. As G.B. Shaw said, "most people would rather die than think". I still defend my postion that the plane would not only take off and fly, but would do so normally, without screeching tires or burning rubber. But I will not defend it to the death.

Friday, January 12, 2007 08:53 AM
Original article: Ask the pilot

Deep thinking

"deep thinking went out of fashion in US society around 1960"

Yes, I clearly remember that, although I was only 5 years old at the time. It happened, if I remember correctly, around 4:35 EST on March 20, 1960.

Tuesday, January 23, 2007 11:47 AM

Why is someone alone?

If someone is alone at 39 it is because they want to be alone. I was alone until 37 because I did not want to share my life with someone. I met someone then and had to make a decision - to share my life or not? I decided to take the chance and it was the best decision I ever made. Of course you have to meet a good, compatible person. But you also have to be willing to transform your solitary existence. Clearly, you want to do this now. Good. Find a decent man with intelligence and an honest character and marry him. It is not up to fate; it is a simple choice you can make.

Friday, January 26, 2007 09:25 AM

Buying a house

Everybody I know who bought a house is crying - all the way to the bank. Every house my parents bought increased in value by 5 to 10 times what they paid. Would you really rather give your money to a landlord to increase his wealth instead of your own? The mistake was not in buying a house, but in buying a "fixer upper" and then fixing it up. What were you thinking? Would you buy an old junky car with the intention of "fixing it up"? I would be depressed too. We bought a house in a very expensive area with excellent schools. It is small. It does not have granite counters. It does not have a jaccuzi. It does not have central air. It is a comfortable place to live that has required no renovations except new siding. The kitchen and baths are 40 years old and work perfectly. I guess it's lucky that I never looked at home magazines.

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