Physics Problem

[steerpike2]

I realize that twine/weight suggestion was a joke. The spool of twine would be ridiculously big. But Even if you use two 10.5-inch reels of tape (these are much thinner than twine)....those aren't unwound. I don't think the tape would hold the metal reel if you let it hang that far down with gravity compounding itself. I've never tried this, though, so I could be wrong...who wants to try it out?

Bah humbug! My post yesterday has not appeared! Lost!
Anyway: a 10.5 inch reel of tape is easily supported by a short length of unwound tape (if you stick it with adhesive so it doesn't all unfurl) - that is the reel weight and the entire 1100m rolled up on the reel. Un-rolling the tape doesn't make any part of it heavier.
Polyester recording tape is extremely strong. It stretches intitially, and rolls up into a tube longitudinally (making it useless for recording), but beyond that, to actually break it, needs an extremely large tension.

I have a roll of radio dial cord here - about fist-sized if you have little fists - that's marked 200 yards. I think thats about half the depth of the hole we calculated. So 400 yards isn't going to be an enormously bigger roll. (I'm not up on yards & feet)

 

[HeezDeadJim]

Bah humbug! My post yesterday has not appeared! Lost!
Anyway: a 10.5 inch reel of tape is easily supported by a short length of unwound tape (if you stick it with adhesive so it doesn't all unfurl) - that is the reel weight and the entire 1100m rolled up on the reel. Un-rolling the tape doesn't make any part of it heavier.
Polyester recording tape is extremely strong. It stretches intitially, and rolls up into a tube longitudinally (making it useless for recording), but beyond that, to actually break it, needs an extremely large tension.

I have a roll of radio dial cord here - about fist-sized if you have little fists - that's marked 200 yards. I think thats about half the depth of the hole we calculated. So 400 yards isn't going to be an enormously bigger roll. (I'm not up on yards & feet)

See I always thought that if you hang from a rope from 100ft rope.....there is more weight at the end (you+all the excess rope) than if you were to just hang from 10ft. I thought the spool acts as a "pulley" to prevent the rope from snapping (besides being conveniently rolled up). In essence, I thought extreme lengths will snap with the same object tied to the end (you) rather than only a short amount of line?

 

[dumptruck]

I think you're missing the point of the post you quoted Heez, but from some rough calculations based on a giant ball of twine on wikipedia, a length of twine the depth of this hole only weighs a little over 5 lbs.

 

[steerpike2]

See I always thought that if you hang from a rope from 100ft rope.....there is more weight at the end (you+all the excess rope) than if you were to just hang from 10ft. I thought the spool acts as a "pulley" to prevent the rope from snapping (besides being conveniently rolled up). In essence, I thought extreme lengths will snap with the same object tied to the end (you) rather than only a short amount of line?

True, IF you keep adding rope, you are adding weight that all tallies up to the total tension in the first few inches.

But with the reel of tape, when it is rolled up on the full reel, the entire weight of it is already present. Unrolling it won't alter the weight. Since a short length of tape can easily be shown to suspend the weight of a full reel, we know that unrolling it will not put any further tension of the top few inches.

 

[toxcrusadr]

It just better have a good connection where it's attached to the real at the other end, because if you drop the reel in the hole it's going to be moving at 100 miles per hour when it runs out of tape!