Here's one to peruse, why not a longer pole?

[souleman]

As I have been reading these posts over the time that I have been on the forum, pole length has come up a number of times. Generally, the questions have been, should I go to a 13 foot pole, or a 15 foot pole etc. For the world class guys, why do they stop with a (roughly guessing here) 16 or 17 foot pole? Is it deemed impossible (because of the physics here) for a world classer to use say a 19 or 20 foot pole. The thought here is that if a world classer can jump a meter or meter and a half above his hand hold, then using a 20 foot pole would net a 23 foot jump. Just wondering why this has not been looked at and discussed. Later.........Mike

[thaone600]

the only reason i can think of is because of the sail piece and it might be really hard to get over it

[rainbowgirl28]

I knew this question had been asked before... spent about 20 minutes looking for it!

http://www.polevaultpower.com/forum/viewtopic.php?t=481

[souleman]

Thanks Becca, my thoughts were that it would be physically impossible to make a pole that long work at all. I'm sure that that was thought about the Petrov model also (the work at all part of my statement). I was sure that I wasn't the first to think of using a longer pole. Clearly the Petrov model (which continually gets beaten to death on this forum) is the "right" way to vault. Doing the model correctly is going to produce a finite result limited by the length of the pole. The model was also a "why didn't someone think of that before" deal, before Bubka. So, that's why I brought it up. Later........Mike
ENTRY #2. Ok, based on the thread that I just read I'm guessing that it would be impossible due to the physics. So why hasn't anyone tried to come up with a way to make the physics work in this case by either an equipment improvement or something as "wacky" as what the Petrov model was back before it was introduced. It would be fun to approach this as purely an "idea" thread and not an "it can't be done" thread. So let's discuss it. What WOULD it take. Later.............Mike

[SKOT]

lets start with someone that has speed like the "GOAT", maurice green and is 6'8"ish.

[polevaultdad]

They are playing with composites and carbon to get a new technology accepted.. But they have not figured out how to get the poles to be safe enough to be approved. If they stay with current technology, the poles would be too large in diameter to grip. Pole vaulters would have to have Mo Green speed, Shaq hands and be built like Manute Bol.

[Mecham]

One word: Flubber

[souleman]

Ok, how 'bout the physics guys with the formulas jumping on board with this one. On the thread that was covering this question the formulas had several different facits. Sort of like Ohms law where Voltage devided by current equals resistance. You can have a multitude of numbers that can yeild the same result or change one value ever so slightly and come up with a completly different result. So, taking the numbers in the "get a bigger pole" thread and vary some of those values (or all of them) to come up with a formula for a bigger pole and a higher height cleared. By varying the "physics" described just a tad, maybe a person could use a bigger pole and clear a higher height. I'm asking us to try to think a little past the "model" and who knows, maybe we all will come up with the next "model". This is how new ideas and things are discovered that once were thought impossible. Later..........Mike

[PaulVaulter]

Change in Kinetic energy = Change in gravitational potential energy

1/2 M Vsquared = Mgh

or h (the change in vertical height)= 1/2 Vsquared /g

so for a guy that runs 10m/sec

h= 1/2 (100)/9.8 ( g is the acceleration due to gravity -9.8 m/sec/sec)

h = 5.10 meters-- this is the change in the vaulters CG

so if the vaulter 's cg is 1.1 m above the ground at take off

then the height the vaulters body can be raised is 5.10 +1.1= 6.20 meters above the ground. The World record is 6.15 meters.

This simplified model, from the other post, tells us how high the pole will lift the centre mass.

This means that if some one ran down with a long enough pole and just held on, i.e. hanging from the top arm, there COG would reach 6.20m. This gives a theoretical grip height of 6.2 + 1.1 = 7.3m (extra 1.1m for distance form COG to top hand).

The energy used to invert is put into the pole by the vaulter after take-off and thus is extra energy on top of that discussed above, so with a push-off of 1m, I am suggesting a theoretical limit, providing there is no energy lost anywhere(which is impossible), of 8.3m!

Admittedly if you were gripping at 7.3 the chances of a 1m push-off are fairly low, but I think it would be possible to lift your legs and break the world record.

Turns out Bubka wasnt that great after all.

Anyone disagree?




P.S. COG is centre of gravity

[skola28]

Basically PaulVaulter is on the right track when he commented on the absolute height; The kinetic model doesn't take into account energy applied after (and including) takeoff. For example, like he mentioned, the energy applied to invert your body is generated after takeoff, albeit some is transferred from the intial energy of the run. There are other factors to add such as 'push off' at the top of the vault, and actually JUMPING off of the ground. Per the previous model, if you didn't run, the maximum height which could be obtained would be 0. But we can all (hopefully) jump over a small obstacle w/o running or even walking for that matter.

As for the maximum pole length. There is a maximum length (obviously) since there is a maximum energy which can be applied to a pole to make it move by any one individual. Currently what limits the length is the speed, strength, and skill of the vaulter. Current materials are a much much smaller factor and poles of 20' are very possible to create (and NO they are not incredibly huge). The carbon fiber poles used by the top athletes are SIGNIFICANTLY lighter (and thinner) than the poles of the same length used 10 years ago. I've played with a Bubka pole from his golden age and it is MASSIVE.

The problem is getting a human body which can control his (or her) top speed, while maximizing their plant/jump/swing EVERY jump. Safety becomes a big issues when you're dealing with 18'+ poles. One small error on the ground is compounded many times over by the time 18' has uncurled!

[Barto]

As for energy input into the system after takeoff....

We know from force plate readings that even elite vaulters are not adding significant amounts of energy into the system from their takeoffs. A "good" takeoff is simply one which directs the energy from the approach into the pole at the optimum angle without a significant loss of velocity.

Other forces generated by mechanical activities of the vaulter tend to diminish the amount of energy imparted to the vaulter off the top of the pole. In other words, the more "work" the vaulter does on the pole, the less efficient the energy transfer becomes.

The vault takes place on the runway. Anything done after you leave the ground is a break even proposition at best.

Barto

[SKOT]

would there be a way to create a pole that gives you more energy back that you gave to it in the first place? that could possibly make it easier to bend a longer pole and still not have it be as soft as a noodle when the pole returns. is this at all possible?

im probably going to get shut down pretty quickly on this one. lets just say physics and science in general arent my thing.