The Naked Scientists

The Naked Scientists Forum

Author Topic: The Physics of Tightrope walking  (Read 5269 times)

lyner

  • Guest
The Physics of Tightrope walking
« on: 28/08/2007 23:04:42 »
This topics has been split from the origional topic " Ice skating, speed and falling over."
http://www.thenakedscientists.com/forum/index.php?topic=9684.0





I'm not sure that I concur. 'Down' would be where something would fall and that would be in a plane, vertical to the earth,s surface and tangential to the instantaneous motion. No centriFUG(?)al force on that object.The 'down' that the cyclist is aware of is, I'm sure' established visually. It' s only on fairground rides that your local 'down', due to acceleration dominates hour visual reference.
I used to be very aware that you could appreciate both alternatives on some rides - but not at the same time; you could switch from on to the other and back again - too much of that and you start to feel sick, though.
The force on you, however, is proportional to v^2 so faster gets more stable.
There are lots of instances where your natural balance system can make you worse off than if you did nothing. Watch someone who is unfamiliar with boats trying to walk around  in a small dinghy.

I thought someone would pick me up on the 'leaning' idea. It relates to balancing on a point and on a tightrope. It really needs another thread. How can you turn when you only have an free pivot to stand on - and I  think you could still do it, even without the cheat of using the drag of the air around you.  Something to do with angular momentum and moment of inertia, I think.
« Last Edit: 04/09/2007 16:18:10 by paul.fr »


 

Offline syhprum

  • Neilep Level Member
  • ******
  • Posts: 3818
  • Thanked: 19 times
    • View Profile
The Physics of Tightrope walking
« Reply #1 on: 29/08/2007 06:41:18 »
A rigid body definitely cannot balance on a point thats why a ballerina has another dancer to assist her!, but wait if you have some means of moving your C of G such as a pole that old time tightrope walkers used to carry or even just moving your arms it is just about possible but it needs a lot of training.
Suitably programmed robots can do it quite easily but then electronics can think faster than you or I.
As for turning on a frictionless point I cannot see a human doing this but satellites do much the same thing by have rotating balance wheels.  
« Last Edit: 29/08/2007 06:47:09 by syhprum »
 

lyner

  • Guest
The Physics of Tightrope walking
« Reply #2 on: 30/08/2007 23:13:47 »
Yes - you can turn as long as the total angular momentum (zero, in the simplest case) is conserved. A person isn't a rigid body and neither is a dancer. Dancers need support because the dance has do be executed without them waving their arms about just to keep balanced. They do, in fact, spend many seconds on pointe, without support, sometimes. Yes, it's training but what is the training actually helping them to do which enables them to keep balanced?
My question relates to balancing on a tight wire and I'd like a good explanation of how it's done which doesn't rely on the use of an umbrella and the surrounding air, which I don't think is necessary in order to balance - it just makes it a lot easier.
 

Offline syhprum

  • Neilep Level Member
  • ******
  • Posts: 3818
  • Thanked: 19 times
    • View Profile
The Physics of Tightrope walking
« Reply #3 on: 31/08/2007 09:30:48 »
The tightrope is pretty rigid back and forth and if the legs are spread to give a broad base then little correction is required in that direction.
The difficult part is correction for the sideways motion of the rope this  can be quite rapid if the tension is high, the body must bend laterally at the hips to keep the C of G above the point of contact on the rope a difficult and unnatural movement that must take a lot of skill to acquire.
also to move forward on the rope the feet must be brought together creating the need for back and forth correction simultaneously no wonder I can't do it!
 

lyner

  • Guest
The Physics of Tightrope walking
« Reply #4 on: 02/09/2007 22:53:45 »
It's exhausting just thinking about it!
 

The Naked Scientists Forum

The Physics of Tightrope walking
« Reply #4 on: 02/09/2007 22:53:45 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums