1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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