Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Question on oscillations spring balance and fish

  1. Jan 30, 2010 #1
    The scale of a spring balance reading from zero to 180 N is 7.00 cm long. A fish suspended from the balance is observed to oscillate vertically at 2.50 Hz. What is the mass of the fish? Neglect the mass of the spring.
    ________ kg

    k =(180-0)/(7-0) = 25.714 N/m

    frequency = (m/k)^(1/2)
    2.5 = (m/25.714)^(1/2)
    6.25 = m/25.714
    m = 160.714 kg

    I am pretty certain this is wrong.
  2. jcsd
  3. Jan 30, 2010 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I think there are two problems. The first is that the equation is actually:

    [tex] \omega = \sqrt{\frac{k}{m}} [/tex] ​

    and you have the reciprocal of that. The second problem is that omega is not quite the same thing as the frequency of oscillation.
  4. Jan 31, 2010 #3
    yeah but what is the spring constant, K. I sort of need that to solve the problem.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook