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Homework Help: Fish pulling on reel

  1. Nov 7, 2009 #1
    1. The problem statement, all variables and given/known data

    A fish takes the bait and pulls on the line with a force of 1.8 N. The fishing reel, which rotates counterclockwise without friction, is a solid cylinder of radius 0.064 m and mass 0.80 kg.

    (a) What is the angular acceleration vector of the fishing reel?

    (b) How much line does the fish pull from the reel in 0.17 s?

    2. Relevant equations

    Torque = Inertia x angular acceleration
    Inertia = 1/2 x Mass x Radius^2 (for solid cylinders/discs)
    Angular Acceleration = acceleration/radius (I personally didn't think this was necessary, but then again I didn't get the right answer)

    3. The attempt at a solution

    I simply calculated Inertia by:

    1/2 x 0.8 kg x (0.064 m)^2 = 1.6384 x 10^-3

    Then I tried to calculate angular acceleration by:

    1.8 N / (1.6384 x 10^-3) = 1098.63 rad/sec ^2

    I was told by WebAssign that this was incorrect...so I entered it as a negative value (-1098.63) in case I was confused regarding the counterclockwise direction of the reel, but this was also considered incorrect.

    I have not attempted part B yet because my approach for part B would involve knowing the angular acceleration.

    Please help!
  2. jcsd
  3. Nov 7, 2009 #2


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    Homework Helper

    Hi premedonna89, welcome to PF.
    I*α = Torque = F*r.
    Try this one.
  4. Nov 7, 2009 #3

    Torque = 1.8 x 0.064


    thank you!
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