NeonBlack

How hot? Depends on the object itself- The geometry, the materials and how fast it's going. How cold? Since there is no air in space, it would only lose heat by radiation so it would cool more slowly than it would on earth. Exactly how fast it cools depends on the geometry of the object. Calculating the trajectory is in principle, fairly simple. The time would probably take a couple of days, but it depends on how fast you go. Essentially all of the energy is used escaping the earth. So it depends how fast you go, how big your object is, how much energy you dissipate in heat. Once you get to a certain distance, the moon's gravity will pull you in the rest of the way. After you escape earth's gravity, almost no energy is required. In principle, going to the moon is easy. Practically, it's much harder.

Cut open your stomach? Just get some from the store! It's real cheap.

You've probably got some HCl in your house. Check the ingredients on the toilet bowl cleaner.

*bang* You're in a better place now, Old Yeller. Hint: Let the people have 0 height. What do you think you need to do? What progress have you made in the problem? What have you figured out so far?

I recently inherited a laptop. It has a 2.7 GHz processor, but only 192 MB of ram. Since the battery life is a little under 2 hours, and I figure that this amount of ram could not possibly take full advantage of the cpu speed, I decided to underclock the processor to save battery life until I find some more memory. My question is how slow can I go without noticing a huge difference? From my memory of PC specs from a few years ago, I am guessing that a computer with 192 MB would have no more than 800-1000 MHz, but I don't know if this is optimum.

You're right that these questions are poorly worded, especially the first one. The problem doesn't say anything about changing speeds, however the resultant velocity will be larger than either of the components. Number 2 is correct. You can move vectors around as long as you don't change the length or the direction. This is a very important property of vectors.

DH: I may be wrong but I was under the impression that there are only 2 "sizes" of infinities: aleph 0: The size of the integers, primes, rationals etc... aleph 1: The size of the real numbers, R^n, C^n etc... The continuum hypothesis is unproven, but generally thought to be true. It states that there is no cardinality between aleph 0 and aleph 1. I once asked an acquaintance of mine, who has many mathematics degrees, about sets larger than aleph 1. If I understood him, he said that he could not imagine that there were any.

m4rc: Actually the "number" of integers and the number of even numbers is the same! The "number" (really called cardinality) of the integers, evens, odds, primes, even rational numbers is the same. It is commonly denoted by the hebrew letter aleph with a 0 subscript. You should read about Cantor and set theory. It is very interesting.

It's certainly possible. However, I think that using radio would be too slow for "high amounts of data at once" and more trouble setting it up than it would be worth. Infrared (IR) is a region of EM waves with a higher frequency than radio. I think it would be fairly easy to find an IR port for a laptop. You also have the added benefit of the FCC not hassling you for unlicensed FM broadcast.

I thought that my cousin had a pitbull when I was young, but now I think it was actually a rotweiler (which also tend to be very aggressive as theirs was).

Mass does not change. Kinetic energy: Energy associated with motion. Rest energy: Energy when an object is at rest. (Duh) The two are completely independant. Again, mass does not change!

I will try to help without giving anything away. Remember that momentum is a vector. Also, the famous F=ma is only true when mass is constant. In general, [math]F=ma+v\frac{dm}{dt}[/math]

You're right. Length is something that we can understand with our primary sense, sight. On the other hand, time is completely abstract. We think we know what time is, but if you ask someone "What is time?" I don't think anybody (expect FS, of course) would be able to give you an answer. SI defines time first as something completely arbitrary- the frequency of cesium-133, and uses this definition, with c to define length. There's no reason we couldn't do it the other way, in principle. We could define length as the wavelength of a certain element's emission line- maybe something a little more common than cesium-133, but again, this is completely arbitrary. (As far as I know, the kilogram is still defined by a hunk of metal locked in a vault in France.) As for mass, looking at your definitions again, what you call relativistic mass is not what is normally thought of as such. I think when most people hear relativistic mass, they think [math]m(v)=\frac{m_0}{\sqrt{1-v^2/c^2}}[/math], where m0 is the "rest mass" This is completely unneccessary. You only need one mass. mass is mass is mass. Under Newtonian gravity, photons do not create a gravitional field as they have no mass, but I believe that in General Relativity, (I am only beginning to study GR) photons do create "curvature" (GR's way of describing g-fields).

I agree it was neat. Although the original "explained" series is entertaining, this is much more concise and coherent. This is a problem I have considered many times. You don't have to use length as your starting point (although it might be the most intuitive- I don't know. This is something I haven't been able to decide on). You can use time. Take some arbitrary time interval. Then we can define length by ct, and you know the rest. I don't want to distract from the main topic, but I suggest you forget you ever heard the words "relativistic mass." Then take "rest mass" and just call it mass.

Why don't you try a flame test, or even a better if you have access, a spectrometer? (I think that's what they call it- the thing that lets you see how much light it absorbs)

Dr. DNA, it sounds stupid to say this, but it wasn't the fall that killed him, but the landing. What I mean is that at the end of a Geronimo (or any impact), pressure is more important that velocity. The way you land determines the pressure. When falling, you will acquire some momentum. When you land, the shorter the impact time is, the greater the force will be. This is why getting hit with a golf ball will hurt much more than getting hit with a pillow, even if they weigh the same and are going the same speed. The second thing is that if the force is distributed over a small area, the pressure will be greater. Consider the difference between standing on the floor and standing on a nail. The downward force is the same in both cases, but for the nail, the force is over the small point of the nail rather than the entire sole of the foot. So, your head is pretty hard and the cross section of your spine is pretty small. I imagine that it would be possible to break your neck even after falling from a fairly small height.

I don't know very much about this stuff. 1. Are neutrons elementary particles? They are made of quarks, the structure of which seems to be the main focus of the article. 2. It says that neutrons are a primary component of atoms. What then are the secondary components? I thought that the most important parts of atoms were protons and electrons. Neutrons are only important for nuclear stability when atomic number becomes large.

Pressing the ice cubes together increases pressure, which lowers the melting point. Water is one of the few substances in which the melting point decreases with higher pressure. This is also how ice skates work. The skates distibute your weight over a small area on the ice. The high pressure melts the ice, which gives you a thin layer of water to glide on.

Didn't we used to have calculus lessons here on the site? What happened to them?

Is it just me, or was Callipygous talking to himself in this thread? I guess the five-hour dungeons will do that to you.

If it weren't, how could you think of it?

I'm guessing it had more to do with the temperature of the pop.

1. Banlist Often, when I notice a user has been banned (by the title by his name) I get curious and end up searching all of his recent posts to find out why. Some forums have a "banlist" which lists banned users, the length of and reason for ban and maybe a reference to offending post(s). 2. Firefox issue When using firefox, clicking on "New Posts" brings me instead to Search for some reason. This is rather annoying. 3. Brain Sprain I noticed that the Brain Sprain thing was abandoned with no explaination. Was this just due to lack of interest? 4. Too many sub-forums? (Just my opinion) There aren't enough posts here that all the sub-forums are needed. I think the site would be much cleaner and easier to browse if some of the subforums were consolidated. That is, have one physics forum, one mathematics forum et cetera... If my memory is correct, this is the way it used to be and I think it worked much better.

Why don't you just use the same one your school uses? Talk to your professor/instructor, he'll probably give you a copy for free. Other than that, without a language or OS, the only other advice I can give is make sure you adhere strictly to the language standards (such as Ansi for C) in your programs.

Wow. I am going to check, but I'm about 90% sure that Po is an alpha emitter. Very bad deal, especially in your lungs. Even if it is found only in extremely minute amounts, I'm sure that after several years of smoking, it has the potential to eff you up.