# Search results

• Users: Nim
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1. ### I Modal Logic - Possibility

One of the ways we use the term possibility is "We can go to Mars". Another way is "We may learn how to travel to Mars faster than light as our understanding of physics progresses". What exactly does it mean in modal logic? Would a statement like 1+1=2 be considered possible in modal logic or...
2. ### I Why Is There No SI Unit For Information?

I was mainly thinking about data storage and transfer rates, these are common categories in unit converters. I thought it was strange that there was no official SI unit of measurement for it since it's something so often measured. Also, I am adding dimensional analysis to a calculator I am...
3. ### I Why Is There No SI Unit For Information?

Why is the quantity "information" missing from the SI system? Also, if they did add it, do you think it would be added as a base unit or dimensionless derived unit?

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5. ### The Holographic Principle

If we do exist on a 2D surface, like a hologram, it does make sense of the idea that all information in a volume can fit onto its area, which is really bizarre. The whole thing sounds crazy to me, it's hard to envision an intuitive understanding of how such a thing is possible. Maybe I just need...
6. ### The Holographic Principle

I first came across this concept in a Scientific American magazine. At the time it was nigh impossible to find much more information on it. Even now I am having a hard time wrapping my head around it. So I have a few questions. From what I understand, it basically says: Every single bit of...
7. ### Pounds is a unit of mass or weight

Ya I know, and distance from the surface adds variation too. But I thought it was the "Quadratic Mean Radius" that gives you the average. But it's the "Equatorial Radius"?
8. ### Free-fall formula, adding air resistance

I just made it up. I found out later that it's also the name of a math game. I didn't realize it would take so much work. I have a friend who knows calculus. But... I think I need a friend that knows advanced calc? and classical physics? I had them look at it just in case, and it was definitely...
9. ### Free-fall formula, adding air resistance

Thank you. Unfortunately, I am math illiterate. I don't know what any of this means, or how to use it. I see 4 equations? I need to arrange them somehow? Like enigmatic Lego blocks? The language is alien to me as well, such as "partial fractions", "separable first order equation", and...
10. ### Free-fall formula, adding air resistance

I finally found something close at this website: http://keisan.casio.com/has10/SpecExec.cgi #1 Sqrt(m*g/k)*Sqrt(m/(g*k))*Log(Cosh(t/Sqrt(m/(g*k)))) #2 Sqrt(2*m*g/k)*Tanh(t*Sqrt(g*k/(2*m))) The problem is that you have to enter TIME instead of DISTANCE... The same website has the ones that...
11. ### Pounds is a unit of mass or weight

Sorry. I know I am dragging out an old thread, but I had to comment on this. Awhile back I was messing around with the equation to find out Earth's gravitational acceleration and couldn't figure out why I wasn't getting 9.81. I kept getting 9.80065745906891. But that was because I was using...
12. ### Free-fall formula, adding air resistance

How do you add air resistance to these 2 equations? #1 sqrt(2 * d / g) = time until impact #2 sqrt(2 * d * g) = velocity on impact The equation for air resistance is: Fd = 0.5 * Air Density * Velocity ^2 * Frontal Area * Drag Coefficient How would you combine this equation with the above...
13. ### Peak Frequency of the CMB

The hyperphysics website gave 160 GHz as an answer using the linear frequency equation. I just have to use a different constant. Thanks for the help.
14. ### Peak Frequency of the CMB

What is the peak frequency of the Cosmic Microwave Background? Using Wien's Displacement (#1) and then converting the wavelength of frequency (#2), I get 282 GHz. #1. 0.0028977685 / 2.728 = 0.00106223185483871 Meters (1 millimeter) #2. 299792458 / 0.00106223185483871 =...
15. ### Gravity And Straight Lines

The explanation I've heard for gravity as depicted by relativity, is that it's the consequence of mass curving spacetime. This means that the reason why the light from a star behind Sun is bent is because evening though the light is traveling a straight line, since space itself is bent...
16. ### Consistant Periodic Table

How do you know what they use for the melting point and boiling point on that periodic table? Are you sure it's consistant, the stp thing only seem to appear with the density about every 10 elements are so.
17. ### Consistant Periodic Table

Im working on a periodic table in vb.net and I want to start adding in the information for the density, melting point and boiling point for the elements. The problem that I am having is I need to find a source that I know has only entered these values for a specific temp and pressure. I prefer...
18. ### Looking for equations

Of course not, I was hoping that you might know of some books or websites that were though. But since that doesn't seem to possible, and since I seem to be confused about some things like unappropriate notation and the use of measurements, maybe you can point me out to a site that can tell me...
19. ### Looking for equations

It's for a program that I am working on. If you type in an equation it looks at it and cuts it up in pieces and takes the parts that looks like a value needs to be added too and puts it next to a texbox. Once I have a lot of equations, I am going to add a search feature so its easier to find an...
20. ### Looking for equations

This site is a lot of help. I didn't find a category about equations, but I did a search and got a lot of results. At the moment I am trying to get a list of the basic science equations. E=M*c² Energy=DynamicMass*SpeedOfLight² Joules=Kilograms*Meters Per Second E=m/sqrt(1-v²/c²)*c²...
21. ### Looking for equations

It doesn't have to be all of them, just a lot. Doesn't matter what kind of equations either. I am mostly spending my time looking for ones that deal with physics. Sorry for not being clear enough.
22. ### Looking for equations

Does anyone know where I can find a website or know of a book with a comprehensive list of equations? I want to know what they do, what units they use, etc... Some sort of reference you know?
23. ### Did you ever wake up and found you were unable to move?

The possum does it. I am not sure what else does. From: A Moment of Science "Possums are famous for "playing dead" when threatened, but this isn't quite accurate. They are not "playing" dead at all: the possum goes into shock when particularly stressed. While not dead, it can be found lying...
24. ### Did you ever wake up and found you were unable to move?

The paralysis that you say "continues" is the kind that doesn't allow you to move at all. That statement suggests that you can't move when you sleep, since you said sleep paralysis is a continuation of the paralysis that occurs during sleep. I don't doubt that "motoric signals sent to the...
25. ### Did you ever wake up and found you were unable to move?

I don't think people are paralyzed when their asleep, because then, you would wake up in the same position that you fell asleep in. And some people move around in bed a lot. Like the sort of people whose foot sometimes ends up in your mouth.
26. ### Did you ever wake up and found you were unable to move?

Everytime I have ever been paralyzed was after waking up. But one time it happened when I went to bed instead and I saw a creature that looked like it was a 3D shadow. The door in my room was open, and it crawled in from outside. It came up to the head of my bed and stood up. After that it...
27. ### Isotope Information

Yes. I am mostly curious about their radioactive properties. The "Table of Nuclides" page that arivero posted has a ton of information. Instead of clicking on different parts of the big colorful blotch you can also pick one part to zoom in on and then click "Nuclide Table" on top to access...
28. ### Liquid wood?

Not all solids turn into liquids. Some solids turn to gas and some gases turn into solids (like snow). The familiar phase changes are melting (solid to liquid), evaporation (liquid to gas), condensation (gas to liquid) and freezing (liquid to solid). But there is also sublimation (solid to...
29. ### Isotope Information

Does anyone know of any book, program, or website that has a ton of detailed information about isotopes? Such how many and what particles they emit (alpha, beta, gamma, x-ray). What the max and average energy those particles have. What range in water and tissue those particles have. What their...
30. ### Awesome Osmium

You can buy a http://www.element-collection.com/html/collections.html [Broken]
31. ### Awesome Osmium

Osmium may be more resistent to pressure, but diamond is still more resistent to being scratched/cut.
32. ### Peak wave deviation

How far from the peak wave do objects emit electromagnetic radiation? Humans emit infrared radiation, but I read that we also emit some microwave also.
33. ### Fuel Cell Electrons

Yeah, I know that.
34. ### Fuel Cell Electrons

That's the part I understand. The part that I don't understand is why they would bother going around the membrane just to reach the protons when there is an anode right there infront of them. Plus the protons are on the negative side. I don't know how far they have to travel to get to the other...
35. ### Fuel Cell Electrons

From what I understand about fuel cells, they generate power by influencing electrons to move themselves around an ion-conducting material to get to the other side. While the electrons make there way from one side to the other, they supply DC in the middle of there journey. But I am not quite...
36. ### Light in the wake of huge objects

Unless the beam of light hits something and reflects off of it, then there is no chance of you observing it since it will continue to travel away from you point of observation and never come back for you to observe it.
37. ### Explosive & Food Calories

A http://muller.lbl.gov/teaching/Physics10/chapters/1-Explosions.htm [Broken] listed what I have posted below. Does it make sense to compare the calories of a chocolate chip cookie to the calories of TNT? Maybe there is more calories in TNT than 1 but not all of it can be released fast enough to...
38. ### Isotope EV & HL

I was looking at a http://chemlab.pc.maricopa.edu/periodic/isotopes.html and was wondering why the half-life was sometimes replaced with electron volts? There's an example from the table below: Helium-6 806.7 milliseconds -> Lithium-6 Helium-7 160 KEV -> Helium-6...
39. ### Discovered Lights Mass?

From: http://www.redcolony.com/articles/030115.html [Broken] "Photon Reaction: Until recently, scientists believed that photons (light) had no mass, but recently, it was discovered that they did have mass. Light has mass. Light is reflected by reflective surfaces. For every action, there is...
40. ### EM Spectrum's Official EM Ranges

How would it be complicated? I know that for me personally, it wouldn't be complicated at all. And this is something that is done for a lot of things to make them simpler. One thing that comes to mind is the network protocol models. And how is assigning different frequencies a range and scheme...
41. ### EM Spectrum's Official EM Ranges

Instead of having things inexact, I think a better way would be to just have more than one standard way of organizing the frequencies that each have a purpose for a certain application, which would make the numbers more meaningful. Their could be a wireless/broadcast scheme, biology scheme...
42. ### EM Spectrum's Official EM Ranges

I just remembered another thing that I was wondering about. The new Blu-ray HD-DVD technology says that it uses a blue laser, more specifically, a 405 nm laser. A lot of sources list 400 nm as the smallest wavelength of the visible spectrum, some others say 390 nm is. Wouldn't something that...
43. ### Why are there substances with different densities

A common analogy used to describe an atom is that if an atom was the size of a baseball field, its nucleus would be the size of the baseball. An atom is mostly empty space, the nucleus has a lot of room to get bigger and more massive in. A helium atom, even though four times more massive...
44. ### EM Spectrum's Official EM Ranges

Different sources show different ranges for the electromagnetic spectrum. Some sources say X-rays range from 10 nm to .01 nm and other sources say that it ranges from 1 nm to .001 nm for instance. I know that it's all really abritrary, but I would like to use numbers that are official or at...
45. ### Why are there substances with different densities

Atom nuclei may have approximately the same density, but not atoms themselves. A bigger nuclei doesn't always mean a bigger atom. What makes atoms bigger is the amount of electron shells they have. The first shell can only hold two electrons. The nucleus of hydrogen is one proton. Which...
46. ### Colour and heat

The shade of the color counts too. I have a dark blue car and it gets really hot when it sits out in the sun. A sky blue wouldn't get so hot.
47. ### Does Light Have Mass?

I always figured that they said mass is conserved because even though you can decrease the amount of mass in the universe, that decrease corrisponds to an increase in energy which can be converted back to mass. Is mass conserved because "anything which has energy has mass" and so the increase in...
48. ### Color Blindness Statistics

I read that the most common form of color blindess (red/green), occurs in 7% of males, but only in .4% of females. Men just have to get the gene from their mother to have color blindess. But women have to get it from their father also. So shouldn't that make it only half as likely for females...
49. ### Strange Chemical Formula

I don't get this: "Its empirical formula is C 10 H 17 N 3 S • 2 HCl • H 2 O" What is with those dots? And the middle part has a number before a letter...
50. ### Energy in the punch

Anyone have an idea of how much energy is transferred to someone or something when someone punches them or it? I know this can vary a lot, but does anyone have any numbers? I came across one website that said something like the "average force of a focused Sieken (punch)" delivers 700...