malmo wrote:
the simple fact of the bank dramatically reduces the sideways forces.
A 200m flat track is slower than a 200m banked track
The centripetal force will push you sideways. On a bank, you will be tended to push up the bank. That means you have to expend potential energy to do that ( it comes from you - no other energy source in the system ), therefore less kinetic energy available.
There is no free lunch.
ventolin^3 wrote:
You may get some psychological effect of running on an even trivial lane 1 banking height, but not a physics one
I'm no physician, but would it not act as a normal force countering the runner's centrifugal force?
forces tend to cause movement
any movement means energy required from basic formula :
Energy = Force* distance
( that applies to sliding horizontally on a track & in this case if it is in a level lane, than the forces involved are centripetal force & countering frictional force of shoes on track, but if overall sideways movement, former is larger than latter with an unbalanced net force until movement stops ( from possible increased lean )
if moving up a banked lane from the force, energy required from
m*g*h
where h = rise
simple conclusion is that if you have movement sideways or upwards, you have a net unbalanced force which requires energy
Let's do away with the formulas and use a little common sense.
Do you really think track cyclists and stock cars would go faster if the tracks weren't banked???
A fit Webb might be able to get within 10 seconds of the WR but I don't think we'll ever see him break 7:30. I'm not a hater, I thought Webb's 3:53 at Pre his senior year was the most exciting race by an American on the track in ages, but let's be realistic here.
kartelite wrote:Let's do away with the formulas and use a little common sense
no
without formulas, common sense can be be worthless
Do you really think track cyclists and stock cars would go faster if the tracks weren't banked???
from above
think hard about the V^2 part of V^2/R
for speeds of
a) 10m/s
b) 18m/s
c) 90m/s
fwiw wrote:
A fit Webb might be able to get within 10 seconds of the WR but I don't think we'll ever see him break 7:30. I'm not a hater, I thought Webb's 3:53 at Pre his senior year was the most exciting race by an American on the track in ages, but let's be realistic here.
3:46 and 3:30 suggest otherwise along with 13:10, what 5-6 years ago?
ventolin^3 wrote:
no
without formulas, common sense can be be worthless
I'm not even gonna go there.
ventolin^3 wrote:
from above
think hard about the V^2 part of V^2/R
for speeds of
a) 10m/s
b) 18m/s
c) 90m/s
What does some old formula for wind resistance have to do with anything? I'm not talking about wind resistance. I remember from racing go-karts and remote controlled cars as a kid that weren't hitting 10 m/s on the curves, and it was definitely possible to go faster on the banked turns.
moron
V^2/R
has nothing to do with wind resistance
Off topic but I can't resist: Ventolin I bet you got great game!
ventolin^3 wrote:
malmo wrote:the simple fact of the bank dramatically reduces the sideways forces.
A 200m flat track is slower than a 200m banked track
The centripetal force will push you sideways. On a bank, you will be tended to push up the bank. That means you have to expend potential energy to do that ( it comes from you - no other energy source in the system ), therefore less kinetic energy available.
There is no free lunch.
ventolin
The centripetal force is by definition what makes the runner follow a curved path.
This force is generated by the runner's pushoff.
It is the *failure* to generate centripetal force that "pushes you sideways".
So for example if the runner decides not to exert energy necessary to follow lane 1
on the turn, the runner will float to the outer lanes.
On a banked track this means going up, and so the runner *gains* potential energy.
This gain in energy comes at the loss of kinetic energy, and therefore a loss of speed.
I think you get this but your terminology is backwards.
Note that this lost kinetic energy can be regained by "falling down" the track again.
But a price has been paid because the runner has chosen to take a longer path at a slower speed.
(Similarly on a flat track if you float outside you have taken a longer path)
Obviously the best strategy is to take the shortest path around, and in this regard
the runner must expend energy to generate that centripetal force. ie hold the curve
What malmo is telling you is that considerably more energy is necessary to hold the curve
on a flat track. It takes a sideways pushoff that is awkward and taxing on the legs
if the turn is tight and the runner is not well trained for it.
On a banked track the pushoff can be similar to the pushoff on the straights.
Mostly down into the track surface. In fact the bank angle can be "tuned" to a
particular running speed.
kartelite wrote:
Let's do away with the formulas and use a little common sense.
Do you really think track cyclists and stock cars would go faster if the tracks weren't banked???
The example is instructive.
The reason they go faster is because a banked track allows for a component of the acceleration to increase the normal force, thereby increasing the frictional force. A banked track is for better traction, nothing more.
The same principle applies to runners. Banked tracks and flat tracks are essentially the same in terms of the force required to round the curve. A banked track, however, for the reasons the poster above me detailed, might reduce some force on the legs because there is less sideways "slipping."
i speak ventolese wrote:
What malmo is telling you is that considerably more energy is necessary to hold the curve
on a flat track.
I'm not saying there is 'considerably' more energy to hold the curve on a flat track, I'm merely saying that there is more energy required.
When you get down to it, the difference between lane 8 and lane 1 on a flat 400m track is so small that you can call it negligible.
The difference between lane 1 on a 400m track and lane 1 on a 200m FLAT track is probably more than the difference between 1 & 8 on the 400m track.
I'm willing to bet that the difference between L1 (400m) and L1 on a banked 200m track is almost back to negligible, especially at 1500m velocity.
Since eldrick has never run on an indoor track he won't understand what I'm talking about. He also won't understand the difference between the engineering of regular board tracks (even at 160yds, 11 laps to the mile, some of them could produce PRs) and that of a 'tuned' track. Modern tuned 200m tracks are much faster than the board track at the Meadowlands that Coghlan ran on.
The engineering of tuned tracks -- Stuttgart, Penn State (same designer as Stuttgart), etc -- is certainly above my pay grade, and Eldricks as well.
Does anyone here think that the track design at STUTTGART's Hanns-Martin-Schleyer-Halle, part of a sports complex that includes the Mercedes Benz Arena, and the Porsche Arena, is merely coincidental? The engineers in Stuttgart take their play just as seriously as they do their work.
Malmo, can you briefly describe what tuning is? I know you said all the details may be above your pay grade but I am not sure even what the basics are.
Thanks.
I don't know exactly what tuning involves. I'm assuming that the tracks are engineered so that you don't get stacked vibration waves matched with the actual 'tuning' (industry jargon for the actual mixtures of surface material) of the track surface.
The Garden track (at least the old one), for example, is not tuned. There are/were dead spots everywhere.
Those of you who think Webb is somehow going to make a miraculous comeback and set all kinds of world records are going to be sadly disapointed.
Webb is now 28 and has not run a serious race in almost 2 years. 1500/3000/5000 runners reach their peak in their mid-20's. This is not to say older runners won't have success, especially in tactical races like the Olypics where veterans often have an edge because of their experience. I'm simply saying that most mid-distance runners run their PRs in their early to mid-20's.
Jim Ryun was 21 when he set his last WR
Morceli was 23 when he set the 1500 WR.
Dainel Komen was 20 when he set the 3000 WR.
El Guerrouj was 23 when he set the 1500 WR.
Bekele was 23 when he set the 5000 WR.
Even those we think of as age-less wonders:
Haile was 25 when he set his last 5000 WR.
Lagat was 26 when he set his 1500/mile PRs (he set a PR in the 5000 at 34, but be honest, what could he have run in his prime?)
Webb may have a future in the 5000 using tactics and what's left of his finishing speed to get by (as Lagat is doing now), but we have to accept the fact that his fastest days are behind him. You can't outrun Father Time.
http://joeposnanski.si.com/2011/01/31/turning-back-time/?eref=sihp
malmo wrote:
i speak ventolese wrote:What malmo is telling you is that considerably more energy is necessary to hold the curve
on a flat track.
I'm not saying there is 'considerably' more energy to hold the curve on a flat track, I'm merely saying that there is more energy required.
Sorry - didn't mean to put words in your mouth. Maybe you would agree the difference is large enough that it matters.
deleuze wrote:
kartelite wrote:Let's do away with the formulas and use a little common sense.
Do you really think track cyclists and stock cars would go faster if the tracks weren't banked???
The example is instructive.
The reason they go faster is because a banked track allows for a component of the acceleration to increase the normal force, thereby increasing the frictional force. A banked track is for better traction, nothing more.
The same principle applies to runners. Banked tracks and flat tracks are essentially the same in terms of the force required to round the curve. A banked track, however, for the reasons the poster above me detailed, might reduce some force on the legs because there is less sideways "slipping."
Note cars & bikes have a firm suspension and travel at a speed such that tire grip is the essential ingredient to turning the corner quickly. A runner wearing spikes does not necessarily have a lateral grip problem on a flat track. However even if grip is adequate the runner still has to spend some energy to avoid turning an ankle. It's about maintaining a "firm suspension" if you will.
ventolin^3 wrote:
There is no free lunch.
I didn't say there was a such thing as a free lunch, I'm saying that the cost of lunch is dramatically lower than you think it is, especially when it comes to a banked track.
Eldrick, you do see that runners on a flat track either 400m or 200m are all leaning towards the inside to compensate for centripetal forces on their center of gravity. When a runner runs on a banked indoor track they are leaning inwards as well, but with a big difference. The angle between body and track surface is at 90º (or close to) - just like he would be if he were running on a straight.
Do you still not see the advantage of banked turns?
( well, a 7'25.00 guy if he started on edge of lane 1 on the curve which may be upto 35cm higher than kerb would be entitled to ~ 0.15s quicker )
Yes he will have a near vertical angle when negotiating the bank in lane 1, but in order to do that he has to rise up the bank in the lane to do that ( higher up he goes, more close to vertical his angle )
If a 6 lane bank is total rise of 2m, then each lane is ~ 33cm elevated progressively & continously ( i used 35cm above )
He will have to be probably near the lane edge with lane 2 to get a near vertical angle, but he he has had to expend energy to rise up to that near 33cm from the level ground of the straight
The price he has had to pay to get the near vertical lean is a debit of ~ 0.15s/curve just for energy consideration in above quoted example ( & that doesn't take into account the extra distance run near lane 2 on the curve than the shortest distance at the kerb, which is ~ pi*1.22 or 3.8m which is an extra ~ 0.5s at 7'25 speed )