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Homework Help: Miniature Bridge design?

  1. May 5, 2014 #1
    So I am the leader of a small group who has to build a bridge in 30 minutes on the last day of school. The only materials we can use are play-dough, straws, and rubber bands and it has to stretch 30 cm between two tables. Though I was looking for some ideas of a bridge design to use. Should I go with something simple like a king or queen post or something more complicated like a solid ribbed arch or a through truss? Any ideas or suggestions would be appreciated.
  2. jcsd
  3. May 5, 2014 #2


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    Staff: Mentor

    Welcome to the PF.

    Can you say more about your own ideas for design options? What are the tradeoffs?
  4. May 7, 2014 #3
    After thinking about the time it would take to do something very detailed, I was thinking about doing a king's post design. The main tradeoff would be time and material. If it is not completed in time or we a end up short a little of materials to finish, then obviously an unfinished bridge is going to fail.
  5. May 8, 2014 #4


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    2017 Award

    Staff: Mentor

    How long are your straws?

    Using them in compression is problematic, tension is easier to maintain.
  6. May 12, 2014 #5
    I assume basic straw length. We get 50 straws and 300 rubber bands.
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