[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 39
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If the bird flies "upright", yes, it will fly. And a baby helicopter will take off. And a large helicopter will take off - no one is stopping them from doing it. But for aeroplane to take off, it needs to have lifting force on wing, wing has to move with certain speed, and minimal speed relative to the air (if we consider that it is stationary, it means relative to the ground). And the plane will be standing still and humming. It doesn't matter what pushes the aeroplane in this case (even though the pilot sprawls with his legs :o)). You can put a glider and pull it with a winch under these conditions - it doesn't matter - it won't take off, either of them.
A helicopter can also take off not vertically, it can drive down the road with its propeller tilted forward. The helicopter has what is known as a propeller tilt device which allows it to move forwards or sideways. And then it's like an aeroplane. You've admitted that the helicopter will take off.
Абалдеть! Извините...
No... - ah, not even... what are you ! ....
PS: the glider is not a good example - it will break everything.
The glider is a very good example. Imagine that the problem is not an airplane, but a glider and it is pulled by a cable (the cable is the equivalent of the thrust of aeroplane engines).
Now stop swinging your horn and think about the problem without any preconceptions and eureka! Everything becomes clear.
В задаче про бочку тогда не хватает исходных данных, чтобы делать правильный вывод. Ответ в этом случае однозначным быть не может.
Oh, come on!
Look, you're standing on a spring and your head is touching the ceiling. And it's balanced so cleverly that there's zero pressure on the top of your head from the roof. You turn it all upside down. Question: With what force are your heels now pressing against the ceiling (the one that used to be the floor)?
Вертолёт может взлетать и не вертикально, он может ехать по дороге, наклонив свой винт вперёд. У вертолёта есть так называемое устройство перекоса винта, за счёт которого он и движится вперёд или в стороны. И тогда он уподобится самолёту. Вы признали, что вертолёт взлетит.
I know a lot about engines (I graduated from the MAI) :o) If you were attentive enough, you couldn't fail to notice that I acknowledged (I didn't even deny) the possibility of vertical take-off of the helicopter in the conditions of the task. Yes, vertically - easily, without straining. And if aircushion would have been used instead of landing gear - yes, it would have taken off.
"Ground - transporter - aeroplane - air is one system.
С планером очень удачный пример. Представь себе, что в задаче не самолоет, а планер и его тянут за трос (трос - эквивалент тяги двигателей самолета).
Стоит теперь перестать упираться рогом и подумать о задаче без предубеждения и - эврика ! Все станет ясно.
With a glider, the problem is different, for the simple reason that the mechanics of the system change (the thrust is external to the aircraft and is transmitted by a cable). And the condition of the problem is not met. The landing gear will just slip. (You just have to be an engineer, not a theorist :o)
Oh, come on!
Look, you're standing on a spring and your head is touching the ceiling. And it's balanced so cleverly that there's zero pressure on the top of your head from the roof. You turn it all upside down. Question: With what force are your heels now pressing against the ceiling (the one that used to be the floor)?
If you turn me upside down, it stays the same. If you turn the whole system upside down, with the force of my gravity.
Вот ближе к теме:
"Игрок поставил цель выйграть в рулетку и довести размер капитала до 100 USD (первоначально у него есть только 36 USD). Он понимает, что самая оптимальная стратегия - не играть вообще, но цель поставлена и есть только 2 возможных исхода - либо проиграть все, либо довести капитал до 100 USD. Правила игры - ставить только на красное, либо черное, если угадал - выйграл столько сколько поставил, если не угадал - потерял ставку. Зеро - потерял ставку. Для определенности допустим, что вероятность выйгрыша = 45% (ну т.е. <50%). Минимальная ставка = 1 USD, максимальная возможная ставка - все доступные игроку деньги. Дискретность ставок для определенности 1USD (ну т.е. цена 1 фишки = 1 USD, фишки нельзя ломать ). Рулетка идеальная (т.е. исходы независимы).
(1)Какая оптимальная стратегия ставок? (критерием оптимальности считать максимизацию вероятности положительного исхода, т.е. вероятность довести капитал до 100 USD -> MAX)
(2)Если еще конкретнее поставить вопрос, то какой размер первой ставки Вы выберете для того чтобы с наибольшей вероятностью достичь желаемого результата, если у Вас 36 USD в данный момент?"
This is a game with negative MO.
It is known to invariably lead to ruin if a large number of bets are placed. In other words, it is not recommended to play it, but it is possible to win. A simple analysis shows that if you have a desire to play and no shortage of cash, a single entry of the entire deposit is an optimal strategy for games with negative expected payout. This minimizes your opponent's stat advantage and thus maximizes our chances of winning by chance.
Going into the game once and up to our tomatoes!
Colleagues, I am dropping out of the argument due to more important matters at the moment. Sorry.
I will not simulate the dynamics of the problem in VISSIM for the sake of it. All in their own way, lyricists and physicists :o)