Mythbusters 10/11/2006 (S04E20) "Killer Cable Snaps"

[Jonathan_S]

I'm surprised that the build team was so negative on the possibility of using a laser to recover audio from pottery.

Yes, there would probably be a lot of noise, but that is what filtering is for.
After all there is a company selling a (really expensive) laser turn table (http://www.elpj.com/) for playing vinal records.
It isn't that much of a leap to using it on pottery.

Also, I didn't notice them being careful to playback and record at the same speed. (Control the speed of the potters wheel). Being significatly off would make it even harder to notice any real sound from all the noise.

[LoadStar]

The pottery myth was a stupid myth. It was one of those that you knew what the result would be even before they tried it. It was a waste of time.

Now, the cable snap one - interesting, but my only question - wouldn't the fact that the cable is snapping into that first steel drum eat a lot of the momentum of the cable? I'd have liked to see them at the end remove the steel drum, and place the pig directly in the center, right next to the steel cable, then sever the steel cable, just to eliminate that possibility.

I'd also have liked to see them construct a rig to hold the pig from the ground, rather than hanging... by hanging the pig, there is pendulum action there that would change the behavior of the cable, versus a cable snapping someone who is standing on the ground.

[YCantAngieRead]

When I was a young kid, one of the school busses from my school got stuck in a ditch. They went to try and tow it out with a nylon rope, and it broke, went through the windshield and killed a child. Not at all what happened in this myth, but proof you should NEVER improperly use a nylon rope.

Which made this one kind of creepy. Second time that a Mythbusters episode has hit me as kind of creepy due to a death of someone I knew.

I was a little shocked they got any sound from the pottery, which I considered cool enough that showing the myth was worth it.

[alansh]

I believe they did also try anchoring the pig so it wouldn't swing so much.

[aaronw]

You know, I'm sure that the navy has had people cut in half by cables, or at the very least killed. 30,000 pounds of force is the most they could get? I'm trying to look up a number for how much force goes through those when they arrest the big planes, but I'm sure it's a really really big number.

[Llwellyn]

It looks like they cut most of the footage of any testing with those stick-on accelerometers, but they were definitely testing to see if the blunt force trauma from the impact would be enough to kill. A couple of quick shots showed the pig with several of them pasted on. They also mentioned several times that "while it would kill you, it just wouldn't cut you in half" near the end of the episode.

[Warren]

don't pigs have thicker skin then humans? i would have also have liked it if the pig wasn't hanging.

I don't know how true it is but I met a lady thru my uncle. I was about 15 and he was going to college with her. she would never drive and I asked him why. he said that once while she was driving the people working on the power lines had let a power line hang down to low and when she drove by her car snaged the cable killing one person. like I said I can't prove that this is true. but I did met this person. so its not a freind of a friend of a guy he knows.

[alansh]

It's unquestionable that people have been killed by whipping cables; it's just the "chopped in two" part that's in doubt.

[Warren]

well yeah I don't know if he was choped in two.

[doom1701]

Both myths were kinda bleh. Even with the cable cut one, there was little chance for wanton destruction.

Now, had they tried snapping some razor wire, that might have been more fun. :)

[heySkippy]

Why didn't they try stretching the cable until it snapped instead of cutting it? Go for the maximum effect, as it were.

I would bet that with more expirimenting and tweeking, the clay pot recording could be made to work.

[jking]

I would guess if they just pulled the cable until it snapped, there would be no way to know where the break would occur and they would not have known where to position the pig.

Kari's got some nice lungs on her, but then again we all knew that already.:D I think Tori's got a little crush on her. Not that I blame him.

[dilorc]

I don't know about cut totally in half, but people have definitely lost feet and legs due to a nylon rope snapping.

In the Navy, pretty much everyone sees the "Synthetic Line Snapback" movie. It's the equivalent of "Blood flow Red on the Highway" for drivers ed.

You could probably be cut in 2, but everything would have to fall into place just right.

[ccwf]

Kari's got some nice lungs on her, but then again we all knew that already.:D I think Tori's got a little crush on her. Not that I blame him.
Tori and Kari interplay about married life together was the highlight of this otherwise blah episode.

[sushikitten]

When I was a young kid, one of the school busses from my school got stuck in a ditch. They went to try and tow it out with a nylon rope, and it broke, went through the windshield and killed a child. Not at all what happened in this myth, but proof you should NEVER improperly use a nylon rope.


They didn't take the kids off the bus before trying to tow it?!?! :eek:

[YCantAngieRead]

They didn't take the kids off the bus before trying to tow it?!?! :eek:
Nope.

Really quite a sad thing that happened. And I'm sure lawsuits were had.

[Tangent]

They simply didn't have a cable strong enough or nearly enough force on it to produce the force required to cut someone in half. Like dilorc mentioned, this is one you hear alot more about in the Navy. The film I saw used dummies, but they were pretty demolished by the lines. The situations we heard about there were when one ship was towing another. Several thousand tons being towed with massive lines vs a forklift pulling on relatively small cable is a big difference...

[pdhenry]

The "real" cable snaps involve a cable stretched it its point of failure. If you're cutting the cable, then by definition you have not applied sufficient strain on the cable to make it fail, and the force of its recoil will be less.

MB is becoming less and less about scientific inquiry and more about good television.

OTOH, in the Jaws boat-pulling myth, we came close to seeing this myth demonstrated on Adam (IIRC).

[ruexp67]

This was the first episode where I really wanted to write in and tell them they were being idiots.

The suspended pig was the most moronic thing I have ever seen. When the cable snapped it would push the pig away before cutting it because there would be no resistance. Standing on the ground, creating friction that would hold you in place AGAINST the line would have been a MUCH better analog.

Expect to see this myth "revisited" on a future show.

[nataylor]

The friction of being on the floor should have little to no effect. The vast, vast, vast majority of the counter force is just going to be inertia for a single-impact event.

And as for cutting versus letting it fail, they had to do it in a controllable, repeatable fashion. That wouldn't happen if they just stretched it until it failed. And again, that shouldn't matter anyways. You can stretch a 20,000 pound cable to 10,000 pounds of force and cut it, or stretch a 10,000 pound cable to 10,000 and let it fail: both should give the same results as far as the amount of force exerted..

[gtrogue]

I don't know that anybody would really be cut in half by a cable no matter what, unless you were rigidly rooted in position and your body rendered inflexible, otherwise you will be "moved" by the force of the cable before it cut through you. Maybe if you were caught between the cable and a rigid body you could be cut in half.

I have seen a nylon rope snap while it was being tugged on both ends. The frayed ends of the rope whipped back and caught the two people pulling the rope on the hands and cut them pretty badly. It was basically like being hit with the end of a bullwhip or lash.
If the very tip of the cable whip cracked on the skin of the pig it most likely would have broken it.

[nataylor]

I don't know that anybody would really be cut in half by a cable no matter what, unless you were rigidly rooted in position and your body rendered inflexible, otherwise you will be "moved" by the force of the cable before it cut through you. Maybe if you were caught between the cable and a rigid body you could be cut in half.Oh, there's no doubt a cable could cut someone in half. It's just a matter of how much force it would take. Take a melon and toss it in the air and cut it with a sword. Same principle, but with a much duller sword and a much tougher melon. But it you can put enough force behind it, it would work.

[ruexp67]

The friction of being on the floor should have little to no effect. The vast, vast, vast majority of the counter force is just going to be inertia for a single-impact event..

Did you see their "table test?" They tested with an obstruction and found that the cable wrapped all the way around it when they used that setup (which was the setup that they used for the full scale test. All it would take is a split second of being in one place before the cable would whip around you and keep you from moving out, I doubt the suspension rig would offer the same support.

Bottom line, I would like to see them retest with an object on the ground that weights 180-200lbs.

[nataylor]

Did you see their "table test?" They tested with an obstruction and found that the cable wrapped all the way around it when they used that setup (which was the setup that they used for the full scale test. All it would take is a split second of being in one place before the cable would whip around you and keep you from moving out, I doubt the suspension rig would offer the same support.

Bottom line, I would like to see them retest with an object on the ground that weights 180-200lbs.
Think about it this way. If you're standing on your feet, how much horizontal force would someone have to apply to your stomach to tip you over? Certainly less than your body weight. That's the only force having the pig touching the ground would offer. It's all about inertia. The cable moves so quickly, it doesn't matter you're suspended in mid-air. It can't impart enough acceleration on you to move you any significant amount whether you're touching the ground or not.

[ruexp67]

Well, we will have to wait until their inevitable "revisit" show to see who is right.

Put a pinyata (sp?) on a table and hit it, or hit while it is suspended from a rope and you will do FAR more dammage to it (even if you hit it from the side) when it is sitting on the table.

[Figaro]

Well, we will have to wait until their inevitable "revisit" show to see who is right.

Put a pinyata (sp?) on a table and hit it, or hit while it is suspended from a rope and you will do FAR more dammage to it (even if you hit it from the side) when it is sitting on the table.
Well that sounds like fun. I guess I am stopping at iParty on the way home.

[nataylor]

Put a pinyata (sp?) on a table and hit it, or hit while it is suspended from a rope and you will do FAR more dammage to it (even if you hit it from the side) when it is sitting on the table.
That depends on the length of time of the impulse. As the impulse time approaches zero, the difference between the two also does.

[nataylor]

FYI, i just did a little experiment. I set an empty soda can on my desk and took a horizontal swing at it with my metal ruler. Then I took another can and looped my headphone wire through the tab and held it up and took a swing at it. Both had the exact same dent on it. You'll have to take my word for it, of course, as I didn't film it Mythbusters-style. I'm still working on finding a Kari stand in.

[ruexp67]

Sorry, I have been spending more time finding a Kari replacemnt, than actual scientific testing. :D