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How much does cable stretch?

  1. Feb 17, 2014 #1
    1. The problem statement, all variables and given/known data
    A 1.25m diameter wrecking ball hangs motionless from a 1.75 cm diameter cable. The wrecking ball is solid and is constructed of steel (density = 7800 kg/m3). If the cable is 16 m long, how much does the cable stretch? For the cable use E = 175 GPa.


    2. Relevant equations
    δ=(FL/AE)



    3. The attempt at a solution

    δ=(FL/AE)

    F=ρ*v*g
    =7800*(4/3)*pi*r^3*9.8
    =78171.66 N

    A=PI*R*R
    =(pi*(1.75*1.75)/4)*10^-4
    =2.4*10^-4

    E=175000 N-m^2

    L=16 m

    When I plug in the values I get 29779.68 m which I know cannot be correct.

    Thanks for your time
     
  2. jcsd
  3. Feb 17, 2014 #2
    Look up what G in GPa signifies.
     
  4. Feb 17, 2014 #3
    I've been working on this problem for 3 hours now because I failed to realize my simple mistake. Thank you a lot.
     
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