[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 422

New comment
 
IgorM: Hooray! I guessed two right answers at once ;) ZS: I'm running to get "off the shelf pie ".
The next challenge will be more difficult :) In the evening.
 
Richie:
The next challenge will be more difficult :) In the evening.


I hope the task will be a little easier than understanding how the market works

ZS: Maybe someone will create a topic on how forex works? Maybe some bright ideas will slip in.

 
The evening will come...
 

A puzzle to solve:

.

Which is greater: The amount of energy that the Earth received from the Sun over a period of 1000 years or the amount of energy that the Earth gave off by radiation into space, over the same period of time? Or are these amounts of energy equal?

PS: The problem only seems simple.

 
Obviously, the Earth is not in thermodynamic equilibrium with its surroundings at the moment (otherwise its interior would have frozen over long ago), from which I cannot but conclude, in accordance with the second law of thermodynamics, that more is given out as radiation.
 
The quantities of energies are not exactly equal of course, but they differ by a negligible fraction. Otherwise the Earth would have cooled or warmed dramatically over those 1000 years. And we do not observe this, judging from history.
 

Apart from the reflected and over-radiated energy from the Sun, there is space:

- geothermal energy

- heat that is released in the process of the surface friction against the atmosphere, which dissipates the kinetic energy of the Earth's rotation around its axis

- heat that is released by water masses rubbing against the bottom of the oceans - dissipation of the rotational energy of the Earth, and the rotational energy of the Moon around the Earth

- ... and a bunch of other smaller factors, but also factors.

 
goldtrader:
The quantities of energies are not exactly equal of course, but they differ by a negligible fraction. Otherwise the Earth would have cooled or warmed dramatically over those 1000 years. And this, judging from history, is not the case.
The Earth's rotation is slowing down, which has been measured accurately enough.
 

Try to estimate what fraction (%) of the Earth's area is affected by direct sunlight. Do not take into account "flattening of the Earth", eclipses and refraction of rays in the atmosphere.

 
We don't observe anything in history - we only have access to a thin layer of the Earth's crust to measure, plus the atmosphere and oceans - and that in itself is a tiny fraction of the Earth's mass, hence even if we recorded significant changes we could hardly say anything intelligible about the subject.
1...415416417418419420421422423424425426427428429...628
New comment