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Homework Help: Cylinder problem:restriction on the height if the radious

  1. Sep 20, 2006 #1
    A cylindrical frame consisting of three circles and four vertical supports is built from 6m of wire, as shown. The frame is then covered with paper to form a closed cylinder.
    1. Determine an expression for the radius r in terms of the height h.
    2. determine the restriction on the height if the radious of the cylendar must be atleast 10.
    I got the first one;
    But I did not get the second one
    10 > 3- 2h/3pi

    3pi(10)> 3- 2h

    30pi-3 > -2h

    (30pi - 3)/-2 < h

    Can someone help me? Thanks
  2. jcsd
  3. Sep 20, 2006 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    A good question would be 10 what? m? Miles? pounds?

    Recall that the lenght of the wire is given in meters, so if you try to make a 10m diameter circle you will have troubles.
  4. Sep 20, 2006 #3
    ^ sorry, 10cm
  5. Sep 20, 2006 #4
    You need to use 10cm=0.1m, as you used 6m initially. Also, I think your < is the wrong way round.
  6. Sep 20, 2006 #5
    ^ thank you
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