SpaceElevator: Why is Cable Thicker at the Center?

[doublemint]

Hi all, I am doing a paper on the space elevator. On the wikipedia site it states that a climber would be far better off on a stationary cable rather than having a cable pulling the climber since "the cable to be significantly wider at the center than the tips". Why does the center have to be thicker then at the tips??

Thanks

DoubleMint

 

[mgb_phys]

What are the forces on the cable at the bottom/middle and top?
Hint - do you need to attach the top to anything?

 

[doublemint]

Well at the bottom of the cable, there is the platform and on top is the station. So there are forces pulling from those two points. Therefore the cable must be thicker in the middle to withstand the forces??

 

[mgb_phys]

There are no forces at the ends

 

[doublemint]

Well there must be some sort of stress on the cable...

 

[DaveC426913]

Well there must be some sort of stress on the cable...

Yes. At the centre. The rest of the cable is hanging down in both directions from the centre.

Ignore one half of the cable for the moment and think of just one cable hanging down from a very tall ceiling. What part of that cable experiences the biggest load?

 

[doublemint]

Thanks for both of your help!