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    Why Do Some Members Implode?

    And so you just left me out to dry? Just like that? You're a total %$#$@#$! I'm outta here!
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    What happens if Sox win tonight?

    Don't forget the Rams. They moved to California in the 40s just when they were getting good.
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    Escape speed and energy

    Yet you still need the mass of the projectile to know total energy. If the mass is not given, you can provide the answer as a number "times m." But, I'm guessing that perhaps the mass could have been determined from the first part(s) of the question?
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    POLL - geographic location of our members

    Vector Sum: Big Boy American (Northeast), with Immigrant mother (Britain) and Canadian Father
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    This is Spinal Tap movie

    The movie is funnier for anyone who has ever been in a band, or at least knew people in a band. "Christmas with the devil" was a big college radio hit, and one of them (not Harry Shearer or Chris Guest, the other one) was part of the the Canadian version of a "Feed the world" type...
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    Harmonic oscillators

    D'oh! I knew that. My bad. And it was right in HallsofIvy's post. Yes, phase angle is the "phi" after the wt, and it does give the "starting point" so to speak, of the oscillation. Phase difference is just that: the difference, in radians, between two angles. Could be the difference...
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    Harmonic oscillators

    The formula A cos wt gives you the displacement from equilibrium. the w (omega, really) is the phase angle.
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    How does anyone get through school?

    Is this your first year of undergrad? I hope not, because I think second year was the worst! If you get past these years, the sheer volume tends to drop. Also (I wish I had gotten this info when I was in college) Don't feel bad about joining the 5-year club! No one cares if it took you...
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    Nice place you got here

    Thanks all. I've already jumped in. God knows why! It's my job to teach physics, and I answer questions all day, so what do I do with my free time? Answer more questions? It's an odd compulsion isn't it? Sort of a "MUST ... FIX ... WORLD " complex.
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    AP problem

    I see the same problem that Galileo sees: The question ought to be "what current will hold the cross-piece at .05 m." For this you just need to balance two equations, one for the force of gravity, and one for the Lorenz force (that's the "BIL" formula). Solve for I. Accoring to "B =...
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    Young's slit experiment question Help me

    You are sort of correct by say "diffraction is less," if you mean that the beam is less spread out. If the slit is widened, the path of the photons would become less uncertain, meaning the photon concentration that falls on the central maxima will be greater. This means greater intensity.
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    Centripital acceleration problem

    Well you have rev/sec. How much distance will an object go in one rev? When you figure that out, you can find the "tangential" speed in m/s, and then your formula might make more sense.
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    Forces and centripital acceleration

    THis is a great problem, but maybe not for the students! Centripetal force must be provided by some other recognizable force. In this case, it is provided by the horizontal componant of the tension. The vertical componant of the tension has to balance the only other force on the chair...
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    Europe looks better.

    Remember, when traveling in Europe, you usually don't stop to see the dirty and dangerous places. When you travel to America, most people go directly to the dirtiest and most dangerous cities ( or they go to the Grand Canyon etc.). If Europeans came over to visit Boulder , or Portland (either...
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    How do i make a FAN?

    Try here: This si for a large windmill, but you can size it down and use stiff paper (like a manilla folder). It's easy to do, take about an hour.
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    Meteor problem

    With the above equation, you need to use it twice! You must find the difference in PE between the two distances from the Earth's center. THe change in PE equals the gain in KE. It occurs to me. Wouldn't it be neat to see a meteor that ignores air resistance?
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    Infra rays question

    This sounds like one of those "flawed" questions that come from a lower-level (elementary or junior high) textbooks. I'm guessing that what the question is getting at is: "which produces more high-energy infrared rays, the sun or a human body." I'm sure you could guess which one. THen, what...
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    Europe looks better.

    Hello folks. Here is my first post in this forum, and I have one word for you: Yogurt.
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    Nice place you got here

    Nice forum you folks have here! IT's so much better than "science forums," I can't tell you! A fellow teacher told me about this site. Most people seem to have a good sense of humor. I have a strong urge to start answering a bunch of questions posted ont the k-12 homework board, but before...