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Homework Help: Pulse wave problem

  1. Nov 17, 2009 #1
    1. The problem statement, all variables and given/known data

    A string of length l = 5 m weighs M = 10 kg . A pulse wave is traveling along the string. What is the speed v of the crest of the pulse, in the uint of m/s , if the tension of the string F is 200 N ?

    2. Relevant equations

    v= sqrt F/u
    u= m/L

    HELP: We can obtain an expression for the wave speed by analyzing the forces acting a string of length l and mass M. Do you recall the resulting relation between the speed of the wave and the tension and the linear density?

    HELP: ....Get the density by defination and then use above equation.

    3. The attempt at a solution

    I tried importing the numbers into the equation what I thought was the equation the HELP statement suggested.. and i got

    v=sqrt 200/(10/15) = 17.320 ... is there something else i should be doing because this answer was wrong but i thought for sure i was doing it correct.
  2. jcsd
  3. Nov 17, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Re: pulse

    The length of the string is 5 m. Where did you get 15 m?
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