How much does cable stretch?

In summary, the problem involves a 1.25m diameter wrecking ball hanging from a 1.75cm diameter cable. The ball is made of steel with a density of 7800 kg/m3. With a cable length of 16m and E = 175 GPa, the question is how much the cable stretches. Using the equation δ=(FL/AE), the attempt at solution involved calculating F, A, and E and plugging them into the equation. However, it was later realized that G in GPa signifies gigapascals, not meters, leading to an incorrect answer.
  • #1
verisimilitude
2
0

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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  • #2
Look up what G in GPa signifies.
 
  • #3
I've been working on this problem for 3 hours now because I failed to realize my simple mistake. Thank you a lot.
 

1. How does cable stretch occur?

Cable stretch occurs when the individual wires within the cable are subjected to tension or pressure, causing them to elongate and increase the overall length of the cable.

2. Does all cable stretch the same amount?

No, the amount of stretch in a cable can vary depending on factors such as the type of material used, the construction of the cable, and the amount of tension applied.

3. Is there a way to measure cable stretch?

Yes, cable stretch can be measured by comparing the length of the cable before and after it has been subjected to tension. This can be done using a ruler or a specialized tension-testing device.

4. Does cable stretch affect its strength?

Yes, cable stretch can decrease the strength of a cable as it causes the individual wires to become more stretched and lose their ability to withstand tension. This can lead to the cable breaking or failing under stress.

5. How can I prevent cable stretch?

Cable stretch can be prevented by choosing a cable with a higher tensile strength for the intended use, using proper tensioning techniques, and avoiding excessive loads or stress on the cable.

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