What Is the Stretch of a Cable Under Load?

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SUMMARY

The discussion centers on calculating the stretch of a cable under load, specifically for a 1.75 cm diameter cable supporting a 1.25 m diameter steel wrecking ball. The user applied the formula δ=(FL/AE) but initially miscalculated the stretch, arriving at an implausible value of 29779.68 m. The correct approach involves accurately determining the force (F) using the wrecking ball's volume and density, and ensuring the area (A) is calculated correctly based on the cable's radius. The Young's modulus (E) for the cable is given as 175 GPa.

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Homework Statement


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.

Homework Equations


δ=(FL/AE)

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
 
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Look up what G in GPa signifies.
 
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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