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Homework Help: DIRE NEED of HELP on HARDEST Physics Problem Ever

  1. May 4, 2008 #1
    Ok, so I am in the middle of what is known as the "axe hunt" at my school. It is the culminating event of the year. The seniors puts together a scavenger hunt that is supposed to take 24 hours consisting of various clues that will require juniors to use their athletic and intellectual abilities. Anyway, to the point - I am an AP mechanics student and the physics problems they gave us this year are E&M problems which I am completely unfamiliar with. The E&M students have been struggling for the last 30 minutes. I have posted the page long problem as an attachment. Any physics gurus want to help save our class some face by solving it?

    If you get the answer feel free to call me at <cell number removed by cristo>; I will be checking the forums every 5 minutes. Once again, the problem is in the attachment

    Attached Files:

    Last edited by a moderator: May 4, 2008
  2. jcsd
  3. May 4, 2008 #2
    If you posted your image on some kind of image site I could give it a shot.
  4. May 4, 2008 #3


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    Or you could just look at the image here :wink:
  5. May 4, 2008 #4
  6. May 4, 2008 #5
    Ok, the seniors just gave us the answer. I may be back with another problem later, but I think this it for now. the answer was .46 rad/s
  7. May 4, 2008 #6
    I'm having trouble understanding the exact set up. The problem so far looks like it is just a bunch of chains to link: an RC circuit has a current flow through the ring, the ring creates an electric field, which then exerts a force onto the charge (the ball), which then starts moving and is acted upon by the lorentz force. Finally the ball crashes into the sphere.

    As far as I can tell, the sphere won't have any angular velocity, and it simply gets a momentum kick from the ball. Are we missing any details about the electric properties of the sphere? Is it somehow polarized? Is it charged?

    Obviously this problem could be very complicated if every consideration is taken into account: the current is not constant and electrostatics don't apply, and the electric field off axis is very complicated (this one was addressed though). How far did you guys get? You are technically supposed to post your work.
  8. May 5, 2008 #7
    My class didn't get very far. I was disappointed, as I am taking AP Physics C: Mechanics, so I could not really help out as I haven't done E&M at all this year. It was pretty much up to Honors physics students who are currently studying capacitance. Anyway, I have a copy of the solution now that the event is over, I'll post it up as soon as I can get my hands on a scanner again.

    We finished the axe hunt 2 minutes past the deadline, so there is quite a lot of tension&controversy on campus right now. I think we are the first class in 154 years not to finish the axe hunt by the deadline.

    By the way, thanks for taking a look at the problem! I will post the solution as soon as I get a chance to.
  9. May 5, 2008 #8
    You should have recruited university ringers. :p
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