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if you want to build a catapult, might i suggest you try tribuchets instead? They are much easier to build and, i think, much more satisfying to use.

perhaps this is the answer.... sorry i don't know how to do the subscript stuff, so this may be somewhat hard to read i think you went wrong when you calculated the the work. As you rightly stated, there is no work in the X direction. Thus, all work MUST be in the y direction. IN other words, all the work that is done is expended to lift the block off the ground. SO you must figure out how high the block is lifted. THis is given by the equation; hieghth = (length of path) * sin(theta) IN this case it is; hieght = 50m * sin(20) Thus, your work equation for this problem should look like; W = F * (delta X) -- where we are only considered with change in the y coordinate W = (55.25N)(17.1m) W = 944.8J thus, power would be... P = (944.8J)/(20s) = 47.24w well, that is the only problem that i saw in your reasoning. Hope that helps some

yes, a tutorial on the suject of using google would be sweet! It could go something like this... Step 1: Ask yourself, "How did I find a science forum on the web on wich to ask this question?" Step 2: Repeat the procces that you used to find this forum, with one minor change -- instead of looking for a forum, look for the answer to your question. Step 3: Reap the benifits of your labor! I will release all copyrights to this process, for the purpose of use on this forum

Right, what skye said. Basically, as long as you are taking a genetics or biochem-like major you are cool. What you should do is the following (only advice)... Pick something that is fairly broad within the field in which you are interested (say biochemistry) and then, in addition to the classes you will be required to take for this major, take any genetics courses and labs that look like they would be relevent to a gentic egineering job (talking to faculty and advisors will be criticle in determining what courses these would be). Most likely this would involve a moleculare genetics lab and one (maybe two) upperdivision courses. I think this would be better than a strictly genetics or genetic engineering major for a few reasons. First, it gives you a much broader appreciation for what is happening in genetics. Second, it gives you more specific knoledge on how all the stuff works (esp if you go the biochem route). ANd third, it will allow you to state on your resume that you have a broader background and thus make you eligable for more jobs, and more attactive to those jobs to which you can apply. But of course you do not have to go this route. ONe thing i will say is take a very broad set of classes...even within your major's area. That is, if you want to do genetics, then you should try to hit up some classes that might pertain to gentics, even if on the fringe. For instance consider classes in the following... biochem physical chemistry supramolecular chemistry evolution linear algebra the list can go on and on. The point being, be brave and explore things that might appear somewhat dubious as far as application to your chosen major might be. You never know when crazy knowledge will come in handy I, for one, have never regretted taking linear algebra. That was a great course, and has come in handy more times that i can care to recall. Anyways, just some advice, take it or leave it. Either way, have a blast in college and enjoy having your job be learning!

what you need to consider is the stability of the enzyme at various ph's as well as the affinity of the substrate for the enzyme at those ph's. It may be that the enzyme is used in basic conditions and as such it would make sense for it to function well at these higher phs. Of course it could just be that your data is erronous...

sup man, just a few quick questions before i go off and about... What grade are you in? (so i have an idea at what level info should be at) What are you thinking the effect of electricity on plants might be? (just curious, but also to help me understand the level of your understanding) Cool, sounds like it could be a rather fun project, and while difficult to some extent, it should give some insights into how science is approached

A physisist, an engineer, and a math professor are all at the same conference. They go to bed in their repsective rooms, and through a freak occurance all three of their rooms catch on fire. THe engineer wakes up and sees the fire, leaps out of bed and frantically looks about the room. Seeing the fire estinguisher all the wall behind him, he rips it off the wall, and proceeds to empty the whole thing out, just to put out a waste basket fire. The phsysist wakes up, sees the fire, and leaps out of bed. Frantically looking around, he spots the fire estinquisher on the wall behind him. He picks up the fire estiquisher, then proceeds to sit down and calculate exactly how much it will take to just put out the fire, then proceeds to put out the fire. The mathamatician wakes up and sees the fire. He then junps out of bed and frantically looks around the room. He sees the fire extenguisher all the wall behind him and says, "Oh good! Their is a solution!" He then goes back to bed.

SWEET! cool, i know a few nerdy jokes... Q: What do you get when you cross a mosquito and a mountain climber? A: Nothing, you can't cross a vector and a scalar.

actually, i think he IS teaching math by saying this. I think he could be trying to make the point that the function of time is not continuous. It has discrete changes AM to PM. Thus, depending how you approach the am/pm barrier (from forwards or backwards) one 12 oclock time may appear to be either am OR pm. It is becuase of this sharp break in the graph of time, that this strange duality occurs (and hence there really is no 12am or 12 pm). Of course, we only travel forwards, so this seems a mute point to most people. However, i think that the concept is well demostrated by using something as commonly encountered as time.

yeah, glow in the dark stuff is cool i think if the vikings were around today, they would be inpressed by how much glow in the dark stuff we have and amazed at how much we take it for granted lol

yeah, or you could just pick them up (or if they are large, weigh them). If the barrels are see-through, you could find how much the difract light. i really like the freeze experiment that yt had, that one is cool.

true and really it all depends on what you are talking about. If you are saying that graphite cannot be compressed, then you are correct, becuase once the carbon starts compressing, it is no longer graphite. It has become diamond. As another (and probably better) example, we can look at the different phases of ice. You can compress ice and it will go through phase changes to more dense phases of ice. HOwever, these are discrete changes and not the smooth compression that we usually think of when talking about gasses. So, you are most certainly correct. Solids (and liquids), as a general rule, cannot be compressed. The point that i was trying to make is this...their rigidity is just do to latice forces that hold the molecules in fixed places. These forces, like almost every other force, can be overcome. Thus, you CAN compress a solid, given enough pressure. The compressed solid remains a solid, however, it may change other properties, and, as such, perhaps it is not really what we shoud properly think of as compression. I suppose that i was just trying to point out that the latice forces could be overcome, and i used a poor choice of non-techinal terms to convey this. sigh...oh well, i guess we can't be precise all the time

sup nicora, i don't see anything wrong with the quote that you supplied, but lets look at it in parts Yeah, this is correct. Essentially, what you are doing when you melt something is to supply enough kenetic energy to the molecules that they break the force of attacktion with their neighbors that holds then in their fixed posioin (this ordered, rigid, posision of molecules in a solid is known as the "lattice"). Thus, the molecules are free to move around , or flow, about eachother and the substance has made the transition from solid to liquid. If you continue to heat the substance, eventually, the molecules will have enough energy to not only move around freely, but to fly away from eachother. In this case, the liquid trasitions into a gas. yeah, this is correct again. In a solid, molecules are held in a fixedc position within the solid's lattice. They are not free to move about in space (or at least their movement is severely restricted). However, the individual molecules still undergo vibrations. So, while the molecules are still techincally moving, their acerage position in space does not change. As an example of this, consider a piano string. When it is struck, it vibrates. Hence it is moving. However, the string does not really go anywhere. It stays in its fixed position within the piano, despite the fact that when it is vibrating it is in motion. I hope that makes sense Ok, so what is being said here is that, despite the fact that the molecules within the solid are clearly moving (undergoing vibrations), the solid as a whole is viewed as a static object. That is, although the molecules within the solid are constantly in motion, the solid itself does not jump about on a table, nor does it randomly change shape. This is clearly seen evereday. If we were to put a brick on a table, the brick would neither change shape, nor would it move without something else moving it. HOWEVER, the individual molecules within the brick are quite dynamic, and are constantly in motion. It just happens that they are fixed fairly well in space, and so we can see that the brick has a definite shape to it. Yeah, so i hope that helps some more. Again, feel free to ask more questions

yuppers, they move, but more on this is just a bit This quote is not really true. The truth is that it is extremely hard to change the intermolecular distances between molecules in a solid, and most liquids. This is why we say that gasses do not have a set volume, while liquids and solids do. Liquids and solids are said to have a set volume per unit mass (or a characteristic density) and as such they are mostly treated as if you could not squeeze the individual molecules closer together. However, if you squeezed really really hard, you could change the density of a solid. Like if you were to but graphite under alot of pressure, it would change density and we would call it a dimond. This is a bit simplistic of an explination, but i think the idea is clear. If you take issue with this explination or want more, then just ask Now about molecules moving in a solid. Molecules DO, in fact, move in a solid. Molecules are constantly vibrating, rotating, and moving from one spot to another (translational movement). In a solid, translational movement is inhibited alot. So much so that molecules in solids generally do not just move about. They are fixed in one spot within the solid. However, they still do vibrate. And as such, they still have motion. Translational movement stops at 0k, not moleculare movement. The molecules are still vibrating. What happens at 0k is that a molecule is in its lowest possible quantum state. But it is still moving. The molecule could not stop moving completely, or it would violate the generalized uncertainty priciple. Well, the definition of solid vs gas just tells us that the molecules are farther apart. It tells us nothing about the relative speeds. In order to calculate the speed of a molecule you would need to know what amount of kenetic energy the molecule has and what its mass is. In order to do this we take the molecules temperature, for temperature is just a measure of average kenetic energy. Then we find the molecules mass and we can determine its speed. But to answer your question. Given an unknown solid and an unknown gas all we could say about them is that the molecules in the gas are father apart than the molecules in the solid. We really cannot say anything about relative speed of the molecules in the gas vs. those in the solid. HOpe that answers your qeustions, feel free to ask more

the register weaker the farther away they are from the epicenter An excellent question! Well, mostly it has to do with timing. We can measure how fast the waves from an earthquake travel through the crust. And we know the distance around the earth. Given this, we can calculate how long it would take earthquake waves to travel around the earth to the point you are measureing them at. Thus, if the waves take a different amount of time, then they must have taken a different path. As it turns out. The waves from an earthquake travel both through the earth as well as around its circumfrence. The waves that travel through the center have a shorter path to travel. IN addition, the material in the inside of the earth is much more dense and, as such, the waves travel faster through this medium. Hence, waves that travel through the earth arrive at the other side much more quickly than do those that travel around the perimiter. THere is more though. Earthquakes produce two different types of waves, p and s types. The p types are caused by compression of the earth. They pressure waves (hence, they are called p-waves ) much the same way that sound is pressure waves in the air. The other type of waves, s waves, are more akin to the waves that we observe when you pluck a gutiar string. That is these waves cause the earth to "vibrate" up and down, in a sigmodail (hence, "s" waves ) fasion. Now, it turns out that p-waves are able to travel in solid and liquids, while s-waves are able to travel in only solids. Thus, as earthquake waves travel through the liquid matle of the earth, the s-waves dissapear, and only the p-waves continue and are measured on the other side of the earth. However, for the waves that travle around the earth, both the s and p types are observed. This is how we know which sets of waves travel through the center of the earth and wich do not. Those that travel around the earth have both s and p type waves, while those that travel through the earth only have p type waves. Many things are learned about the interiour of the earth by measureing this waves. Many (if not all!) of the assertions made about the interior of the earth, find their basis in the measurments of earthquake (real or artificial) waves. It pretty cool stuff really. Anyways, i hope that was a decently clear explination, however, feel free to ask more questions, yours have been most excellent so far!

hmmm...interesting argument. I like it But of course, just for the sake of argument, i will step to the plate. Your argument assumes two things (actually three) things. 1) Psychic abilities is an advantage 2) It is large enough of an advantage to be selected for 3) The gene for psychic ability is not located near to a gene that is detrimental to survival. As far as assumption 1 goes, perhaps there are drawbacks to this ability. LIke depression resulting from being able to see the future. Or perhaps knowing the future causes you to act more cazily than if you did not. On the whole, however, these seem to strech a bit, so i would agree that psychic ability would seem to lend an advantage. At the very least, being able to see the future or far away doesn't seem like it should be disadvantagous. Which leads us to point 2. That is, that psycic ability is not strong enough to be infuenced by selction pressures. If something does not really effect us one way or the other, then it is not really selected for. Take wisdom teeth, for instance. For the most part, having wisdom teeth is a disadvantage, for they do not really fit into our modern mouths. Thus, having wisdom teeth can cause great pain or infection when the emerge. However, it is not really that much of a disadvantage, becuase we know how to deal with these problems now. As such, there is really not much pressure being exerted for or against wisdom teeth and the frequency of wisdom teeth just kinda floats around in a population. This is known as "genetic drift." The point being that this could also be the case with pychic abilities. That is, they are advantagous, but not really all that much, so there is not a whole lot of selection pressure selecting for it. THus, we find that psycich abilities would not really be selected for. Lastly, the psychic gene could be located really close to a gene that is heavily disadvantageous. Perhaps a gene associated with parkensins disease or something. Thus, the harmful gene would be selected against and the psycic gene would reduce in frequency as a result of this. Well, i lied, i guess there is one more reason. Perhaps psychic abilities are present in potential but the ability to use them must be learned. Thus, since psychic abilites are somewhat dismissed in our society, most people would not ever learn how. This is not really a genetic reason, but i thought i would throw it out for fun Anywyas that is my thougts for right now. Cool.

I doubt that argon would work becuase it is pretty darn inert. By the same measure, we did not evolve to breath nitrogen, even though it is the major component of air. This is becuase the chemistry of nitrogen is not conducive to life (it kinda hard to do things with). As far as the original question goes, i dont think that oxygen could be considered a drug, because it does not alter the natural operation of your bodily functions.

if you mean carboxilic acid, then sure there are lotsa ways to do it. Do you need to know particulare methods?

what do you mean by fragmentation and regeneration? If you were a bit more specific about what you are looking for, perhaps i could be of assistance. Cool

If you specify the frequency of light you are also specifying the wavelength. (frequency) * (wavelength) = (speed of light) since speed of light is constant. Specifying frequency or wavelength specifies the other as well. Thus, frequency affect (or rather, determines) color.

Well, actually, i think Franklin agreed with my position... "May not the knowledge of this power of points be of use to mankind, in preserving houses, churches, ships, etc., from the stroke of lightning, by directing us to fix, on the highest parts of those edifices, upright rods of iron made sharp as a needle...Would not these pointed rods probably draw the electrical fire silently out of a cloud before it came nigh enough to strike, and thereby secure us from that most sudden and terrible mischief!" Here, "draw the electrical fire silently out of a cloud" i think clearly means avoiding lightening. Of course, just because Franklin thought this does not mean it is correct. SO, i dug out some of my old physics texts. The following is from Phsysics the nature of things by Lea and Burke; "The sharply pointed [lightning] rod is connected to the ground. As a thundercloud approaches, charge leaks from the ground into the air through the rod's point. The dischafe is rapid enough to reduce the risk of a lightning strike. If the connection to the ground is broken, the rod becomes a hazard. Instead of reducing the nearby concentration of electric charge, it becomes a relatively easy path for the lightening." I think this is fairly clear that they view the lightening rod as reducing the chance for a lightning strike. I think this is fundamentally different than a lightening rod. These rockets are fired up durring the hieght of a storm. They are not in place up in the air as the storm approaches. As such, the are not really given suffecient time to discharge the electrical charge. Thus, the become more like the lightening rod that is dosconected from the ground. They serve as a attaction for lightening. Actually, with most of todays modern buildings, lightning strikes are not that dangerous to the occupants (at least not directly). Most of the modern buildings have a steel inferstructure. This metal skeleton effectively yeilds the building a giant faraday cage, and offers ample protection from flowing electricity. Moreover, the elevator, as a metal box, is probably one of the safest places to be, should lightening strike a building (at least as far as the electrical currect from the strike goes). By the same measure, people in planes that are struck by lightening are also pretty darn safe. The real problem seems to be that lightening strikes can really wreak havoc with a buildings electrical system. And malfunctioning electrical systems can cause bad things (failures, fires, ect). I think that is really the problem with lightning strikes, at least as far as tall buildings go. Well, i don't know if this is really good evidence, as sample size = 1. Also, what would be the frequency of lightening strikes without the rod? Also, i did some reasearch. There are rods that DO attact lightning. They are usually dull where as the ones that do not attrat lightning are sharp. So perhaps we are just talking about two different stypes of lightning rods Yeah, i suppose it could work. However, you wouldn't really want the lightening to strike the laser would you? You would have to insulate it alot or something. I think that all depends on how much/fast the charge is put into the air. If it could dissipate it, then it wouldn't really attact the lightning more. At least i don't think. I guess i would have to sit down and see how fast the electrstatic attrachtion changes due to desity of charge field. Perhaps i will try to figure this out and post it up. Cool.

I think that this thread is baised on a common misconception? This misconceptoin is that the lightning rod is MEANT to be stuck. If memory servers, the lightning rod has the exact opposite intention. It is put places you do not want to be struck. The way this works is as follows. You put the lightning rod up real high somewhere where you don't want lightning to strike. Then you ground it. Then, durring a thunder storm, all the positive charge goes up to the highest point (the rod) in order to get closer to the negatively charged clouds. Since i lightning rod is sharp, it is able to dissipate charge into the surrounding air. Thus the lightning rod, in effect, is meant to take charge from the ground and dissipate it in to the air. Since there is less positive charge in the ground, lightning is less likely to strike in arreas around the lightning rod. At least, i think this correct. I think i remember being told this in my E & M class. Cool

Yes, at least most of the universities in the US will, as long as you are getting your Ph.D. in a science. In alot of the other diciplines (liberal arts, history, ect.) they either do not pay you, or do not pay you as much. Well, you go to school and they pay you to do it. There are basically two reasons why they do this. First, in most universities, you have to teach courses at least for part of the time you are there. So they are paying to teach (and what they pay you is cheap for a university educator, so they are really getting educators on the cheap) Second, you do research why you are their. SO they are paying you for your research. Again, paying someone 21,000 a year to do research is very cheap. I was making about 30,000 dollars in science even before i got my bachelors, just working as an intern. So while you are at the university, you take a HUDGE pay cut, from what you would make should you be working in the real world. In exchange, they teach you some cool stuff and give you a degree. Hopefully i just filled you in. HOwever, if you want more information, feel free to ask

that is exactly correct. In fact, there was a lab at Lawrence Livermore National labs that was doing things along these lines. They were growing plants in C14 free/limited environments, then harvesting the plants and dating them (come on, i no us scientists have bad social lives, but PLANTS? you gotta stick to your own species, man) Anyways, the plants appeared to be much older than they actually were. It was kinda cool, though expected.

exactly cool, now to clear up a few other things, just for your own personal edification... the way you phrase this, it makes it sound like the nucleaus goes through a gradual degridation process, much like your shoes. That is, your shoes just kinda slowly wear down until one day, you can't use them anymore. This, however, is not how nuclear decay works. Carbon is either carbon 14 or carbon 12. There are not stages between. So, in nuclear degredation, it is like you have a carbon 14 atom sitting around and then BAM!, it releases a particle and now it is carbon 12. Yeah, so the point being, radioactive decay is a stepwise mechanism and not a gradual process. That is why we have to look at the ratio of carbon. If we were to just look at an individual atom we would find that it is either carbon 14 or carbon 12. This would tell us nothing. But the ratio of these carbons DOES tell us something. But i think you have grasp that Cool. Well, like i said, if you have any more questions, please don't hesitate to ask