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C051109 - Suspended balls

PostPosted: Thu Nov 05, 2009 11:57 pm
by El Mundo
Entirely new to this, however I trust you'll get the gist of the challenge...

Using no more than 96 rods construct a free standing, self supporting structure designed to hold the maximum number of joined spheres between no more than two anchor points.

Got that?

See picture for crude example, wherein 4 joined spheres are suspended between 2 anchor points.

What's the maximum you can achieve?


Re: C051109 - Suspended balls

PostPosted: Sun Nov 08, 2009 12:13 pm
by El Mundo
OK, my bad. I got my sums wrong, you are allowed up to 144 rods to achieve your goal.

My best score? 15 joined spheres.

Re: C051109 - Suspended balls

PostPosted: Thu Nov 12, 2009 3:05 pm
by El Mundo
Well, you've had a week and still no takers?

I haven't built the answer yet so you have more time, if anyone is actually trying this one, that is...

Re: C051109 - Suspended balls

PostPosted: Fri Nov 13, 2009 11:53 am
by Peter Jepsen
I want to give it a try but I have been busy and did not find the time.
Don't wait with the 'solution' just because of me, I'm fine with participating later.

Re: C051109 - Suspended balls

PostPosted: Thu Nov 19, 2009 9:04 am
by karlhorton
I've been able to suspend 12 quite convincingly, but now stuff is starting to explode!

Point of clarification: I presume that the chain of suspended balls (control yourself, PeterJ)
must not touch anything except sphere at the endpoints?

I'm suspicious because in the small example you gave it looks a little like the end
balls might be cradled by the tetrahedron's edges, in which case you kinda get two
for free.

Re: C051109 - Suspended balls

PostPosted: Thu Nov 19, 2009 10:03 pm
by Wim
Using a Supermag structure I had laying around on my desk (for a suspended ball), I figured I could modify it and try this challenge. Right now I'm looking at 12 suspended balls and am probably pushing this construction's limits. I'll have to try it with Geomag and see what I can do. I haven't really had much time to experiment lately.

Re: C051109 - Suspended balls

PostPosted: Fri Nov 20, 2009 4:02 pm
by El Mundo
Karl -

The example does show a degree of cradling, however in my solution (which I promise to build soon and share with you) the chain of spheres hang from the two endpoints and touch nothing else.

As you approach 15 spheres things do get a bit jumpy (I nicknamed the construction 'Buckaroo' precisely because of this tendency) but it can be done - just...

Wim -

I've never had a go with Supermag so I'm not aware of its limitations. I'm happy that people are trying this challenge, it shows that interesting problems can be explored with only a small amount of Geomag! A lot of the amazing constructions shown in these forums are simply beyond me as I don't have enough stuff to get even close.

I'd be interested to see pics of your constructions so far to see how they differ from mine

Re: C051109 - Suspended balls

PostPosted: Fri Nov 20, 2009 5:38 pm
by Wim
A bit jumpy is right... I'm at 15 right now. May play with it a bit more after lunch... And I'll try to remember to bring a camera in on Monday for a picture.

Re: C051109 - Suspended balls

PostPosted: Mon Nov 23, 2009 3:58 pm
by Tychi
My best result is 14 balls.

Re: C051109 - Suspended balls

PostPosted: Mon Nov 23, 2009 6:01 pm
by El Mundo
Nice work Tychi, your design is much simpler than mine! However there appears to be contact between the spheres closest to the anchors and the blue rods holding the anchors at the bottom - not allowed I'm afraid. Should be fairly easy to fix and I also think that with a delicate touch you may get the 15th sphere in place.

While I was working on this problem, it occurred to me that there may be an absolute maximum number of balls that can be suspended this way. Now I don't know enough about magnetic fields to be able to support this, however with Geomag there is a maximum number of magnets you can attach to any one sphere. Does it follow then that the magnetic field is limited, and therefore the number of balls? Does the distance from the anchor points play a part in this too? Suppose I should've listened during physics lessons...