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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?
    rad/s2

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

    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

    rl.bhat

    User Avatar
    Homework Helper

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

    Torque = 1.8 x 0.064

    *blush*

    thank you!
     
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