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!

Tension in a rope, wavelengths, etc. I need help!

  1. Dec 5, 2011 #1
    1. The problem statement, all variables and given/known data

    A rope is stretched between two vertical supports. The points where it is attached (P and Q) are fixed. The linear density of the rope, u, is 0.6kg/m, and the speed of the transverse waves on the rope is 12 m/s.

    a. what is the tension in the rope?
    b. with what frequency must the rope vibrate to create a traveling wave with a wave length of 4m?

    The rope can support standing waves of lengths 4m and 3.2m, whose harmonic numbers are consecutive integers.

    c. find the length of the rope
    d. find the mass of the rope
    e. what is the harmonic number of the 4m standing wave?

    2. Relevant equations


    3. The attempt at a solution

    a. (0.4 kg/m)(12m/s)^2= 58N

    b. f = (12m/s)/(2m) = 6 Hz

    c. n=4

    2L = 16 for both
    Last edited: Dec 5, 2011
  2. jcsd
  3. Dec 5, 2011 #2
    u = 0.6kg/m or 0.4kg/m?
  4. Dec 5, 2011 #3
    Oh, it's 0.6kg/m. Sorry it's kind of late and I guess I'm just tired of trying to solve this problem :I hehe..
  5. Dec 5, 2011 #4
    Is not the wavelength 4m?
  6. Dec 5, 2011 #5
    No, you're right. It's 4.
  7. Dec 5, 2011 #6
    Am I doing these correctly?
  8. Dec 5, 2011 #7
    Length of rope = 8m
  9. Dec 5, 2011 #8
    yeah i got that :) thanks! do you know how to do D or E though?
  10. Dec 5, 2011 #9
    re D
    Your post says,'...The linear density of the rope, u, is 0.6kg/m,...' and you know the length of rope.

    re E

    What do you understand by 'fundamental frequency'?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Tension rope wavelengths Date
Rope's tension Today at 4:34 PM
Find tensions of ropes that are attatched to a steel beem? Mar 14, 2018
Tension force of block and rope Dec 12, 2017
Tension of a rope Dec 4, 2017
Tension in a rope wavelength Jul 24, 2007