?

This isn't homework so it may not have a solution

And how do you explain that these are two equally real manifestation of the same phenomenon without contradicting each other?

It's just an impression I have whenever I'm swimming by the beach. The recurring periods last for several minutes. They seem pretty regular so I wonder if they have a physical explanation (which is odd); or maybe it's just my cognitive dissonance..

My big math-exam question... None of my friends knows how to solve it either so good luck!

Follow-up question was "Give an example of a non-invertible A such that there doesn't exist a X that satisfies the equation".

At first I was amazed by the mysterious way wave functions collapse by our mere knowledge of which slit they went through. Then I learned that essentially it's due to the measurement device firing photons on the electron, which is kinda lame because of course it isn't really the same experiment.

Can we use a detector that doesn't influence the electrons? For example measure the change in a electromagnetic field by an electron to determine which slit it went through.

So what I learned is:

If A=

a b

c d

Then A^(-1) = 1/det(A)*

d -b

-c a

But with the general method A^(-1) = 1/detA * adj(A). For adj(A) you just draw a vertical and horizontal line on the element and calculate the determinant (and multiply by -1 depending on position). However if I draw those lines on the orginal right upper corner in b I should get c right? So I think it should be:

A^(-1) = 1/det(A)*

d -c

-b a

I understand the physical explanation that hot molecules will conduct heat easier in a solid bcs they are close together than in a gas. But:

- Why does a volume of stone heats slower than a volume of air?

- Why isn't the soil warmer than the air above it?

- Why do we put on jackets if they would conduct out all of our heat?

- Why do houses use solid isolation instead of liquid or gas isolation?

- Why doesn't all the heat of mercury in a thermometer escape by the surrounding glass?

- etc.

It's just not so intuitive for me :/

Shower thought..

Thanks

Imagine the FCC structure. For each corner of the cube, take the three nearest neighbours (these are on the faces). If you place a cation in the middle and connect everything, you get a tetrahedron. And since there are 8 corners, there are 8 tetrahedrons possible within the FCC structure. If you look closely at the diamond cubic structure you'll see that only 4 of them are used, in an alternating symmetrical fashion.

My question is, why not all 8? Because that would make the structure even stronger, right? If it is possible, has it been tried and how is it called?

I just finished my first year of mechanical engineering and have some free time this summer. I want to maximize the use of that time by picking the best possible summer job/internship/volunteer work/... that would boost my resume. Should I choose something that highlights leadership, communication, teamwork, work ethic, technical skills or something else? I know all of these are important but which ones are the most important?

After college I would want to be a process or R&D engineer in the industry sector.

Ye6s,I'lactuallyse6rious.Tnhe6space6barisbroke6ntoo

Istnhe6ke6yboardruinh6ednhow?CanhIdryitwitnhsoe6tnhinhg??

Ple6ase6NHELP

You get employed at a job with a salary of s money/day and start with no money. Every day you can choose to either receive your salary OR decide to take a day off and become more efficient. This means you apply some function f(s) to the salary (only dependent on the current salary).

What is the best general strategy to get the most money after X days, given the function f(s)?

Bonus: for what function wouldn't it make a difference?

This could either be really hard or really easy, but I'm curious to the answer since it would have a lot of applications (eg. planning versus working dillema's). 5 points to whoever can make the most progress!

Imagine a frictionless skier at height y1 going off a skiramp, that ends with a ledge of height y2. He flies after the ledge and lands at a point x. Only consider gravity and reactionforces of the ramp, forget friction etc.

Does the height y2 influence the distance x? I'm guessing not bcs potential energy is the same. But why do all skiramps opt for a ledge in this case (that has friction!)?

How do I solve

(2x + 5y)y' = x-y

Best answer gets five stars!