/sci/ - Science & Math

Hello :3
Can someone explain me that? plz

A 70kg swimmer jumps off a 10.0m tower. If his descent is stopped 2 sec after it enters the water, what was the average upward force exerted by the water on him?

The picture is there just So I can upload also nice Dogie ain't it.

A number is an object that describes the size of a set.
The whole numbers is the set that contains all objects that describe the size of all sets.
The Integers are the the location of any object to any given set.
The rational numbers are the objects that describe the ratio of two sets with one another.
Real numbers are the objects that describe the variance of any set.
Finally the the set of all numbers is defined by the relation of all objects to all other objects defined by any and all sets.

A number is an object that describes the size of a set.
The whole numbers is the set that contains all objects that describe the size of all sets.
The Integers are the the location of any object to any given set.
The rational numbers are the objects that describe the ratio of two sets with one another.
Real numbers are the objects that describe the variance of any set.
Finally the the set of all numbers is defined by the relation of all objects to all other objects defined by any and all sets.

A majority of the world's freshwater fish eat mosquitoe larva at one point or other in their life cycle.

Hello /sci/,
I usually go to /g/ by default, but I ended up getting no responses over there so I decided to come ask you all.

Is there any ASCII transcription of the ET messages @ NSAdotGOV/public_info/_files/ufo/key_to_et_messages.pdf

Or has anyone other than the NSA attempted to decrypt the messages that start on page 9 of the pdf?

Time does not exist. What most people consider time is merely the measure of cyclic physical occurrences.

Biology. Physic follows cut and dry rule. I.E. Acceleration equals the change in velocity over time a=(Vfinal-Vinitial)/Time ) Biology follows generalized trends.

>>6929521
too early to celebrate, meh. that gives 1=1 when simplified :/

>>6929469
man I love you!

thanks :)

p.s. solution in the image

well, it repeats but it is kinda a tough one. here's what I've got so far

starts to repeat at some point when trying to solve with integration by parts. I'll just see if I can move from there and share the result here for curious people!

and I didn't know there were symbols here, as said, newbie :)

can you help me integrate this fellas?

f is a function of n.
fp = f prime = df/dn

integral [ fp(1-fp)dn ]

>>6126329
Add-on for clarification:

If the velocity is constant, produced by a constant force being applied to something, such as pushing a crate x meters, wouldn't the acceleration be 0?

>>6126329
Right but I thought the definition of acceleration was a constant change in velocity over time.

Over time, there is not chance in velocity over time, instead, the velocity remains constant. If the velocity is constant, wouldn't the acceleration be 0?

T = tension
m = mass
If T is a constant force, then the acceleration a = T/m also is constant.

I'm sorry, if you have a constant force applied to something, the acceleration would be 0. Assuming T/m doesn't equal zero, how can this possibly be true? How can you have a constant nonzero acceleration (x meters per second, per second) if you have a constant tensional force being applied to something?

But technically, a neanderthal is not a human being.

Solar power might be safer and more efficient. Set up the panels on the serface and rund cables down to the shelters.

Interesting perspective. I've tried a few approaches so far I'd like to share with you as you seem experienced.

Approach 1: Learn only as much as you need to -- focus on coming up with something new.

Result 1: Felt like I wasted a lot of time learning extremely domain-specific knowledge that couldn't be easily transferred to other areas.

Approach 2: Learn all the basics first avoiding research papers (even review papers).

Result 2: Still somewhat trying this strategy since I felt like I made the most strides with this. This is liable to me learning a lot of "obvious" things from the point of view of researchers and not enough on learning, as you said, the current state of affairs.

Another problem with approach 2 is that I can't always easily locate good references that help me quickly get up to speed on some material. I agree practice and diligence are necessary and I'm willing to sacrifice a lot for it.

I feel like I'm heading towards approach 3 which is also inefficient -- sort of jumble approach 2 with keeping up with some research papers in a particular subset of what I'm interested in.

This thread has been lacking some imagery, I'll put up some eye candy. (Sorry for double post)

>>4330793

Interesting perspective. I've tried a few approaches so far I'd like to share with you as you seem experienced.

Approach 1: Learn only as much as you need to -- focus on coming up with something new.

Result 1: Felt like I wasted a lot of time learning extremely domain-specific knowledge that couldn't be easily transferred to other areas.

Approach 2: Learn all the basics first avoiding research papers (even review papers).

Result 2: Still somewhat trying this strategy since I felt like I made the most strides with this. This is liable to me learning a lot of "obvious" things from the point of view of researchers and not enough on learning, as you said, the current state of affairs.

Another problem with approach 2 is that I can't always easily locate good references that help me quickly get up to speed on some material. I agree practice and diligence are necessary and I'm willing to sacrifice a lot for it.

I feel like I'm heading towards approach 3 which is also inefficient -- sort of jumble approach 2 with keeping up with some research papers in a particular subset of what I'm interested in.

This thread has been lacking some imagery, I'll put up some eye candy.

>>4330762

I've heard one professor and one graduate student (and indirectly another professor) plug nanohub. I watched a few lectures on x-ray diffraction and perhaps my background is lacking, but there seemed to be two levels of difficulty I kept encountering -- the entirely too easy and the beyond me. I haven't found much to bridge the gap. Would you recommend something/someone in particular on nanohub?

Thanks for your suggestion. I thought all the comments on a lazy Saturday on /sci/ were going to be squandered on people insulting each other over trivial matters.

Well, I read a book on general chemistry. I know a little organic chemistry. I know bits and pieces of physical chemistry but I have never read a book on it. I have had some exposure to quantum mechanics. I tried to read a bit of Griffiths book but the pace was frustratingly slow and that's considered one of the best if not the best book on it.

Electromagnetics I think I know decently, but I could always stand to get a refresher on it. I want to finish up Griffiths book on it soon. I half-heartedly read through it a while ago when I was in a hurry.

Solid state physics... I've tried to read Ashcroft and Mermin and it's tough. I need to know quantum mechanics well before I delve into it I think.

Thermodynamics I have seen in a few classes and I'm currently reading a proper book on it.

Statistical mechanics I have never read a book for it formally either, but I think I know little tidbits here and there.

I have some experience with semiconductor processing technologies, but I don't know best practices, I don't know the history of it fully, etc.

Characterization methods I somewhat know, but I could do a lot better with optical methods in general. Maybe even some of the electron based ones like TEM I could learn more about.

Electrical layout I know the general idea and it only really seems useful if you want to start making stuff look professional and final. Perhaps I'm wrong and it is more useful in higher frequency devices such as for RF, etc.

Plasma physics I know virtually nothing about and I don't think it'll be all that relevant to know deeply what's going on just yet. If I ever get access to a plasma deposition system like PECVD, then sure. But it's lowest priority.

Hello everyone.

I want to research in new memory technologies. My background is that I am an electrical engineering undergraduate student. I feel like my EE undergrad curriculum did not prepare me very well for what I am interested in.

I know somehow general chemistry, organic chemistry, physical chemistry, quantum mechanics, electromagnetics, solid state physics, thermodynamics, statistical mechanics, semiconductor processing technologies, characterization methods, electric circuit layout and maybe even a little plasma physics are all relevant at worst and very important at best.

But I'm having quite a bit of difficulty efficiently learning it all and being able to retain all the knowledge.

What resources would you all recommend?

I am aware of the trolls with nothing better to do and that I will have to suffer them to seek out the really brilliant people here. Oh well.

It does not mean time travel. It just means Einstein was wrong.