CPL.Luke

I've been to a community college, and it demanded a rigour level less than that of highschool, and i've heard the same story about every other community college i've known of. People get out of the CC and head to the university and they practicly fail out because the CC hadn't prepared them, and in fact a lot of them do fail out. i've heard the statistic that only about 20% of CC students will eventualy get a bachelors degree, mostly because of the gap between CC and university.

if you watched the video the guy pretty much gave everything away in a relatively untechnical manner (he was talking to investors for the most part). he's planning on publishing a paper in a journal soon, and was funded by the navy for the pst ten years. this guy is real, and he is presenting real science

I have some thoughts on the community college system in the US that I'd like to here your oppinions on. so right now in many states there are dozens of small community colleges that offer verpoor curriculuums, few courses, and in general just cause problems for their students once they transfer to a larger university that demands a far higher level of rigour in the school work. So my question is wouldn't it be better if states built larger campuses to accomidate all of the students? by the basic principle that a larger school is a better funded school, and can offer more diverse classes, and provide for a better experience than a small community college. In order to pay fore these larger campuses the school could absorb the funding that normally would have gone to the community colleges and then agree to admit a certain numbr of students from that county every year. any thoughts?

I meant when superimpsing two waves traveling in the same direction, sorry I should've been clearrer

oh of course, he did do alot of interesting things, but by the time he got to wanderclyffe he was a quack

keep in mind he's a comedian, maybe he was trying to be nutcase like kramer was and bombed, you never know

thanks m4rc by any chance can you post the film? hmm so now we can say that two mechanical waves cannot be superimposed on eachother in a string, but what about for soundwaves and electromagnetic waves which could easily be superimposed on eachother?

he was pretty much a quack, there is no free energy to be had. however he did create something called a tesla coil which applies a very high voltage to a sphere causing electrical arcing, tesla created one that could through arcs over 120 feet!. note however that these things use very low current and you could easily stand in the middle of the arc storm and not feel a thing.

hmm well as for bounce back, as long as the oscillation of the center point has twice the amplitude of the original two waves, hen the wave traveling down the other string should have twice the amplitude. we could also do away with the string and look at power in an electromagnetic wave the formula for this power is E^2/c and we look at this and see that if you superimpose two waves on each other than the power becomes 4 times the power of one wave. you could accomplish this through some kind of lensing system I'm sure, but then you have the problem that you put 2P energy in and now it appears that your getting 4P energy out.

there are always problems of being cool and not being cool, its part of growing up, realising that all that you need is to have some good budies, and a direction. you don't need to conform to someone elses idea of what "cool" is. back in the sixties the billboard top 40 used to tell you what music to listen to if your cool, now we have people telling us what clothes to wear to be cool, its not that big of a deal. I went to a very wealthy public highschool (wealthy enough that the school had flat screens in the hallway) I lived in a trailer park in that town. I never had a problem wearing cheap clothes from the good will or old navy etc. I like the way I dress and nobody ever criticized me for it. also learning how to dress yourself properly is an important skill for later on in life, whether you like it or not the way you dress attracts certain people, gives others some impression of you etc. (helps with the ladies ) its good that kids learn about this. EDIT: my school also had the dress code that essentially made it so that people couldn't show up naked, i agree with this as it makes it difficult to concentrate if the person next to you is half naked.

I think a general experiments bored is a better option, there are plenty of experiments out there. and then later f its a success we could start to split it up into subsections.

D H Here's sevarian's point and after looking at your post I belive that we are all in agreement, its just that were talking about different problems. If you lock the problem into one dimension so that you have a rocket of length L a fuel tank and a thruster all perfectly balanced along at the origin along any set of axes made perpendicular to the the line from nosecone to thruster. and assume that at the beginning the center of mass along the L axis is located in the fuel tank. the thruster begins to fire and ejects mass out the back end of the rocket, after some time the center of mass of the rocket (not including the ejected mass) has shifted towards the back end of the rocket slightly. and after the fuel tank has been completely emptied the center of mass will lie at the the center of the rocket along the L axis. now in this problem the total momentum of the rocket (just the shell, again not the expended fuel) is going to be exactly equal to the negative of the momentum carried by the fuel in the opposite direction. it does not matter what path the fuel took along its one dimensional trip (whether it zigzaged back and forth between the fuel tank the nose cone and the thruster several times before being shot out of the thruster doesn't matter) to get the final momentum all that you need to look at is the ejected mass. however if your looking at the total discplacement of the rocket from where it started its burn, your going to need to take into account the center of mass change. The problem becomes a bit more complex when you add in the possibility of the center of mass change along multiple axis, thus allowing the possibilty that the thruster will cause the rocket to change direction and possibly spin do to the change in the vector between where the force is applied and the center of mass. but the final momentum of the rocket will be exactly equal to the momentum carried away by the fuel in the opposite direction of the rocket. one other point however, in your zero thrust rockets, you kept insisting that the velocity of the ejected mass relative to the rocket was 0 this would mean that the mass would not move away from the rocket and would infact stay with the rocket.

hmm i think I see the difference, in the US you learn the basic trig functions and all when you first enter highschool (age 15) in a course called geometry which covers lengths and angles and such. then the following years involve alot of extra algebra and trigonometry. So we learn all of the trig identities before going into calculus. I was starting to think that in europe you guys were two years ahead of us.

I meant the 22 move rule

on what? unfortunatly string theory went for a long time without producing any do or die predictions (and it still hasn't), the theory is more a thing of mathmatical interest than scientific at this point, as you can build none string supersymmetric models and all that. So the theory doesn't really add any predictability to anything, and even more so its founding assumptions are just bad science. Why should the fundamental particles be made of vibrating strings? why not vibrating spheres? or elipses? or purple monkeys doing a happy dance? Also its possible that the LHC could find some supporting evidence that string theory is really what the universe looks like, but that same evidence can work in other existing theories, and even if the LHC doesn't find anything to support string theory, you can just formulate a version that said that it shouldn't have found any evidence. this is not good science. This comic sums up string theory rather nicely http://xkcd.com/c171.html

So I take it you think the hopper will move?, or the rocket of post 40?

but what about in my setup with the Y? at least temporarily two identical waves will be traveling down the bottom of the string, and because I was only putting 2P amount of power in those waves only have 2P power available to them and yet they should be exerting 4P power

or in the case of a circle a line thats perpendicular to the radius and only touches one point on the circle.

oh you meean a recursive integral. (I think thats what they called it) I thought you were talking about double integrals for some reason. Second year physics majors didn't know how to do that?

^you haven't posted in a forum other than General Discussion these posts don't count. I just got into physicsforums.com out of curiosity Ecoli and D H do you use the same name?

if the water exits the hopper with zero velocity relative to it, then there is no ejected momentum.

ah see now in the system that your describing the water does not leave the hopper with zero velocity. If I understand you correctly your placing your hole to the side of the hopper, in which case the fluid will be propelled by the pressure etc. inside of the hopper and generate some thrust. I thought we were placing the hole directly beneath the hopper in which case the hopper won't experience any thrust. The point however is that the final momentum will ony depend on the total momentum ejected from the hopper. (note this is the only the final momentum, the momentum before the fuel flow is stopped will depend on the internal fluid movements) but like I said I thought we were just looking at two different mental diagrams and that appears to be what occored.

I know from personal experience that if hydrogen is mixed in with the air in the proper ratio it is highly explosive. Also I had a friend at the university of Iowa, they got hold of a 5 liter water jug, filled it with hydrogen and blew it up in the middle of the road. it apparently made a decent sized pot hole.

on the subject of SI versus imperial units I'm a freshman physis major in the US, and the last time I saw an imperial unit in a science classroom I was in grade school (up to age 14 in US) Physics ust doesn't make sense without SI units, who the hell woul want to measure mass in slugs?

this reminds me of anouther poll that showed a majority of people believed clinton handled taxes better than bush, even though he raised taxes and bush lowered them. It just goes to show that the American people are more than mere sheep, and can see that you can't spend a billion dollars a day in Iraq and lower taxes at the same time.