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Physics2013
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Homework Statement
An object of mass .5 kg is hung from the end of a steel wire 2m in length and .5mm in diameter. The mass is lifted a distance h and then dropped (creating a 'jerk') What is the largest value of h if you don't want the wire to break?
Ultimate Strength: 1.1E9 N/m^2
Young's Modulus: 2E11n N/m^2
g=9.8 m/s^2
A=Pi(r^2) = Pi(0.0625) mm^2 = Pi(6.25E-5) m^2
Homework Equations
F = -kx = ma
h=mgLo/AY
k= -AY/Lo
The Attempt at a Solution
I know the ultimate strength may not be exceed w/o wire breaking. So
Force(down) < or = 2E11 N/m^2
But, I am unsure of what the force(down) would be with the given information.
Force(down)=mgh ?
= (AY/Lo) x , where x=2h ?