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Homework Help: Crazy salad spinner?

  1. Nov 18, 2012 #1
    1. The problem statement, all variables and given/known data
    You grew up with a salad spinner that operates with a string attached to a wheel with a radius of 6 cm.
    Unfortunately, the string broke last week and you need to get it working again before Thanksgiving. You
    need to figure out how strong the replacement string must be in order to survive the holiday without
    breaking. Under normal operations, it takes 0.2 sec for you to spin the salad from rest to 5 revolutions per
    second. The basket of the spinner has a radius of 12 cm. You normally put 0.1 kg of wet spinach in the
    spinner and you decide to make a conservative estimate, so you make calculations assuming that the
    spinach is at the location that requires the most torque to get the spinner moving. What torque does the
    string exert on the axle, and how strong a string do you need?

    2. Relevant equations
    torque = I(angular acceleration)

    3. The attempt at a solution
    I found the torque to be 0.23 Nm, but have absolutely no idea how to find the strength of the rope from there. Should I find tension?
  2. jcsd
  3. Nov 19, 2012 #2


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    Science Advisor
    Homework Helper
    Gold Member

    Yes. The string has to be capable of applying a force (=tension) via the 6cm radius wheel so that it produces the required torque.
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