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Homework Help: Waves & SHM, HELP

  1. Jan 28, 2009 #1
    1. The problem statement, all variables and given/known data

    To measure the acceleration due to gravity on a distant planet, an astronaut hangs a 0.060-kg ball from the end of a wire. The wire has a length of 1.5 m and a linear density of 3.1 multiplied by 10-4 kg/m. Using electronic equipment, the astronaut measures the time for a transverse pulse to travel the length of the wire and obtains a value of 0.098 s. The mass of the wire is negligible compared to the mass of the ball. Determine the acceleration due to gravity.

    m=.06 kg
    l=1.5m
    linear density= 3.1 multiplied by 10-4 kg/m
    t(time)=0.098 s
    a=?

    2. Relevant equations
    v=d/t
    v=√ F/linear density
    F=ma



    3. The attempt at a solution

    v=dt
    v=1.5 x .098
    v=.147

    v=√ F/linear density
    .147=√ F/3.1 multiplied by 10-4 kg/m
    .0216=F/3.1 multiplied by 10-4 kg/m
    .0216 x 3.1 multiplied by 10-4 kg/m=F
    F= 6.699e-6

    F=ma
    6.699e-6=.06 kg x a
    a=1.12e-4

    my answer was WRONG!
    Why??
     
  2. jcsd
  3. Jan 28, 2009 #2
    Well, in your Relevant Equations you state that v=d/t (which is correct) but in the first step of your solution you seem to use v=d*t.

    It might just be as simple as that.
     
  4. Jan 28, 2009 #3
    Wow, thank you sooooo much, its funny how little mistakes can make a mess out of a problem!
     
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