GENERAL DISCUSSION

[CharlieP]

If anybody's still reading this thread,

Will an aircraft on a treadmill going in the opposite direction at the same speed take off?

A prize is hidden behind one of three doors. You pick one, and somebody who knows where the prize is opens one of the other two to show that it's empty. Should you stick with your first choice or change to the other?

[en1044]

The Monty Hall problem, eh?

[CharlieP]

Originally Posted by en1044

The Monty Hall problem, eh?

[Alemanniafan]

Originally Posted by CharlieP

If anybody's still reading this thread,

Will an aircraft on a treadmill going in the opposite direction at the same speed take off?

A prize is hidden behind one of three doors. You pick one, and somebody who knows where the prize is opens one of the other two to show that it's empty. Should you stick with your first choice or change to the other?

1. That of course depends on the speed of the treadmill, on the minimum speed at which the airplane can take off, on the point (or points) of reference to which the relative speeds are being measured or defined and on the airspeed relative to that reference point.

2. I choose door 3!

[CharlieP]

Originally Posted by Alemanniafan

1. That of course depends on the speed of the treadmill, on the minimum speed at which the airplane can take off, on the point (or points) of reference to which the relative speeds are being measured or defined and on the airspeed relative to that reference point.

Actually, all it depends on is whether the aircraft has wheels or skids, and whether the pilot has left the brakes on.

2. I choose door 3!

Let's open door 1. No prize there. Do you want to stick with door 3 or change to door 2?

[warpus]

Originally Posted by Marckymarc

For the same reason it would take a whole second to go from 1:00 to 00.59.9 Einstein.

Why would it take a full second to go from 1:00 to 00.59.9? That's one tenth of a second. 10%

[Alemanniafan]

Originally Posted by CharlieP

Let's open door 1. No prize there. Do you want to stick with door 3 or change to door 2?

In that case I'll quote an old stubborn lady in funny sketch :

"Hey!!! - I picked door 3!!! - Why did you open door 1, young man?!?!
I didn't pick door 1, I picked door 3!!! ..."

The old lady then of course continues argueing endlessly how unfair it is, that the moderator wouldn't open the door she picked. And the staff of the show then try to explain the rules to her again and again, but she of course just keeps nagging on that she picked door 3 and not door 1 ...and why the moderator refuses to open door 3 ...and why he would bother to ask her to pick a door in the first place, if he just opens whatever door he wants... and so on...

[Rev Stickleback]

Originally Posted by CharlieP

If anybody's still reading this thread,

Will an aircraft on a treadmill going in the opposite direction at the same speed take off?

No. Its airspeed would be zero, so no lift.

Put it is a windtunnel, on the other hand...

A prize is hidden behind one of three doors. You pick one, and somebody who knows where the prize is opens one of the other two to show that it's empty. Should you stick with your first choice or change to the other?

That was a good one. Wiki really can be your friend.

Think of it as a million doors, and the guy shutting 999,998 of them, and it becomes more clear that it would be a million to one chance that you'd have picked correctly first time, so you switch.


If one man walks up a mountain at 6 am, and gets to the top at 6 pm. The next day he walks down, starting a 6am, and reaches the bottom at 6 pm. Will there be a point where he was at exactly the same height at exactly the same time as the previous day?

[Aceventura]

The box! The box! I'll take the box!

[CharlieP]

Originally Posted by Rev Stickleback

No. Its airspeed would be zero, so no lift.

Bzzzzt! Wrong! It has airspeed because its engine(s) or propeller(s) push it through the air. All the treadmill can do is make the wheels spin twice as fast.

If one man walks up a mountain at 6 am, and gets to the top at 6 pm. The next day he walks down, starting a 6am, and reaches the bottom at 6 pm. Will there be a point where he was at exactly the same height at exactly the same time as the previous day?

Of course there will. It's impossible for that not to be the case, since the ascent and descent have to cross at some point.

[Marckymarc]

Originally Posted by CharlieP

If that's the case, then at the start the timer should instantly switch to 11:59.9 once game time starts.

EXACTLY. BINGO. Ding Ding Ding--we have a winner.

I was beginning to think I was living in the Twilight Zone as this is the first response in more than 3 pages that agrees with the bloody obvious conclusion that the clock should instantly read 11:59.9 when the referee drops the puck.

Originally Posted by CharlieP

markymarc is claiming that it doesn't, but I want to know how he can make this claim, given that he has no way of knowing when the timer has been started.

Simple observation while attending WHL and NHL hockey games. You watch the referee drop the puck for the period opening face off, then glance up at the scoreboard and notice that it takes roughly 1 full second for the clock to tick down to 11:59.9

[woozoo]

Originally Posted by CharlieP

Bzzzzt! Wrong! It has airspeed because its engine(s) or propeller(s) push it through the air. All the treadmill can do is make the wheels spin twice as fast.

Think about it. If we're talking about something like a Cessna, most of the air around the plane isn't moving. Only the air in front of the engine, and this air which is pulled past the body of the plane. If Doanld Trump was standing near the tip of the wing, I doubt his hair piece would even flutter.

A jet plane would suck all the air through its engine/s which would mean no air passing past the body/wings at all.

A plane will only take off if there is enough lift generated by air travelling over its wings. A plane normally generates almost all of this lift by travelling at speed through (relatively) still air. In the case of the treadmill conundrum, none of this lift is created as the plane (and the planes wings) are not moving. The only lift generated comes from air pulled by the proppeller flowing over the wings near the body of the plane. I imagine that there are very few planes (if any) light enough, with strong enough engines and the right body design to generate this kind of lift when completely still.

Of course there will. It's impossible for that not to be the case, since the ascent and descent have to cross at some point.

You're ignoring the most important part of the riddle, which is the man must be at the same height at exactly the same time as the previous day.
For this to be the case, the man would need to be travelling at exactly the same speed constantly going both up and down the mountain.

[en1044]

I am officially changing my position on the subject, though I won't go 100% because I would have figured that something like this would have been noticed a LONG time ago. Because of that, I'm still skeptical.

The clock during a basketball game starts as soon as the ball is touched. So at the jump ball to start the game, whatever guy touches the ball while it's in the air means the clock should start. A full second does indeed pass from the time the ball is touched to the clock showing 11:59. I'm positive that the timer is looking for the exact second the ball is touched because my uncle used to do the score at my basketball games and he would tell me how he did it.

Here's proof. Go to 57 seconds in.

[Marckymarc]

Originally Posted by en1044

I am officially changing my position on the subject, though I won't go 100% because I would have figured that something like this would have been noticed a LONG time ago. Because of that, I'm still skeptical.

The clock during a basketball game starts as soon as the ball is touched. So at the jump ball to start the game, whatever guy touches the ball while it's in the air means the clock should start. A full second does indeed pass from the time the ball is touched to the clock showing 11:59. I'm positive that the timer is looking for the exact second the ball is touched because my uncle used to do the score at my basketball games and he would tell me how he did it.

Here's proof. Go to 57 seconds in.

Yep, exactly. 20 minutes and 1 second--as plain as the nose on your face.

Thanks for the video proof.

It happens in the NCAA, NBA, NHL and every other sport that uses the tenth second clock. One extra second per period.

Glad to see at least a couple of others now see it's a fact and not a figment of my imagination.

As for not being 100% sure, just trust your eyes, math skills and common sense, not what something "ought to be" simply because no one up to this point (other than me and now you) has noticed.

-

[Alemanniafan]

Originally Posted by Marckymarc

Yep, exactly. 20 minutes and 1 second--as plain as the nose on your face.

Thanks for the video proof.

It happens in the NCAA, NBA, NHL and every other sport that uses the tenth second clock. One extra second per period.

Glad to see at least a couple of others now see it's a fact and not a figment of my imagination.

As for not being 100% sure, just trust your eyes, math skills and common sense, not what something "ought to be" simply because no one up to this point (other than me and now you) has noticed.

-

Yeah! Hoooray! You're right! And the video also proves that the world indeed is a disc because the basketball court is all flat!

Geez what the f... did I do all this annoing explaining for if, you don't even bother to read what I wrote to explaint it to you.

I'm not gonna explain it again. Feel free to believe a gameplay takes one second longer than it should and that noone else in the world was ever clever enough to notice beore you did.
Feel free to believe the landing on the moon was just a hoax and filmed in some studio. Or even feel free to believe 9/11 was an inside job.
I really couldn't care less, I tried to help you understand by explaining to you how clocks work if they operate scientifically correct.
What you do with my explanations or the explanations from others, is really just up to you and not to anyone else.

[CharlieP]

Originally Posted by woozoo

Think about it. If we're talking about something like a Cessna, most of the air around the plane isn't moving. Only the air in front of the engine, and this air which is pulled past the body of the plane. If Doanld Trump was standing near the tip of the wing, I doubt his hair piece would even flutter.

A jet plane would suck all the air through its engine/s which would mean no air passing past the body/wings at all.

A plane will only take off if there is enough lift generated by air travelling over its wings. A plane normally generates almost all of this lift by travelling at speed through (relatively) still air. In the case of the treadmill conundrum, none of this lift is created as the plane (and the planes wings) are not moving. The only lift generated comes from air pulled by the proppeller flowing over the wings near the body of the plane. I imagine that there are very few planes (if any) light enough, with strong enough engines and the right body design to generate this kind of lift when completely still.

You've made the common mistake of assuming that the treadmill has the ability to hold the plane back, in the same way that a treadmill can keep a car from moving forwards. This is not the case. As soon as the propeller(s) or engine(s) start pushing air backwards, the plane will start moving forwards through the air. The treadmill won't negate this forward movement and give a net movement of zero, since the wheels are free to rotate.

Imagine holding a toy car on a moving conveyor belt. You will be able to walk alongside the belt, pushing the car along, no matter how fast the belt turns in the opposite direction - all it can do is make the wheels spin faster.

You're ignoring the most important part of the riddle, which is the man must be at the same height at exactly the same time as the previous day.
For this to be the case, the man would need to be travelling at exactly the same speed constantly going both up and down the mountain.

Not the case at all. Imagine if there was a time machine at the top of the mountain, and it sent him back in time by one day. Then both he and his earlier self will be setting off at 6am - no matter what speed both walk at, or what breaks they take, they must cross at some point. That point, no matter where it is, answers the riddle.

[CharlieP]

Originally Posted by en1044

Here's proof. Go to 57 seconds in.

Look at the shot clock though.

12:00 - 35
11:59 - 35
11:58 - 34
11:57 - 33
11:56 - 32

I think this is actually proof against the OP's argument:

1. The shot clock must surely start at the same time as the game clock. It wouldn't make sense to have to press an extra button to start the shot clock, and it's extremely unlikely that it would take almost exactly a second to do so (note how the shot clock appears exactly in sync with the game clock).

2. The only way to explain the discrepancy is that the shot clock "rounds up" and expires the instant it hits zero, whereas the game clock rounds down/hides the decimals.

3. The above is totally consistent with the evidence:

Before the game starts (12 minutes remaining): 12:00 - 35

0.01 seconds into the game: 11:59.9 - 35
0.99 seconds into the game: 11:59.0 - 35
1 second into the game: 11:59.0 - 34
1.01 seconds into the game: 11:58.9 - 34
...
34.01 seconds into the game: 11:25.9 - 1
34.99 seconds into the game: 11:25.0 - 1
35 seconds into the game: 11:25.0 - 0

[en1044]

Shot clock doesn't start until a team has possession. That's the whole point. You wouldn't start the shot clock when no team had possession would you?

You can clearly see the GAME clock start as soon as it is touched, and the SHOT clock start as soon as North Carolina has possession. The two hardly ever run together.

[CharlieP]

Originally Posted by en1044

Shot clock doesn't start until a team has possession. That's the whole point. You wouldn't start the shot clock when no team had possession would you?

Pardon my ignorance of basketball.

[Rev Stickleback]

Originally Posted by CharlieP

You've made the common mistake of assuming that the treadmill has the ability to hold the plane back, in the same way that a treadmill can keep a car from moving forwards. This is not the case. As soon as the propeller(s) or engine(s) start pushing air backwards, the plane will start moving forwards through the air. The treadmill won't negate this forward movement and give a net movement of zero, since the wheels are free to rotate.

That's right. There would be some drag caused by the wheels spinning, but not enough to slow the plane enough, probably.

Not the case at all. Imagine if there was a time machine at the top of the mountain, and it sent him back in time by one day. Then both he and his earlier self will be setting off at 6am - no matter what speed both walk at, or what breaks they take, they must cross at some point. That point, no matter where it is, answers the riddle.

Or just imagine two climbers. They'd have to pass at exactly the same height, at exactly the same time.