I Rotational stability and Fosbury Flop questions

  • I
  • Thread starter Thread starter John3022
  • Start date Start date
  • Tags Tags
    Center Gravity
AI Thread Summary
The discussion centers on the physics of stability in high jumping and cycling, particularly the Fosbury flop technique and the dynamics of bicycle stability at higher speeds. It highlights that there is no single equation for bicycle stability; rather, it involves a collection of interrelated equations and parameters. Gyroscopic precession is noted as a key factor, where increased speed reduces the precession rate for a given torque. The conversation also touches on different types of stability, including slow, gradual changes versus rapid, potentially dangerous shifts like a "tank slapper." Overall, understanding these dynamics is crucial for both high jump techniques and bicycle safety at speed.
John3022
Messages
2
Reaction score
0
TL;DR Summary
Why are rotations more stable the faster they rotate and what is the consequence of the fosbury flop?
What is the consequence of the center of gravity passing below the rod in the high jump? Fosbury flop.
Which equation is responsible for a bike being more stable the faster it's driven? and in rotating things in general being more stable the faster they're rotating.
 
Physics news on Phys.org
Welcome, John!

Please, see:
https://www.pbs.org/newshour/science/the-not-so-hidden-physics-of-your-favorite-olympic-event

high-jump-physics-03-1200x675.png
 
John3022 said:
Which equation is responsible for a bike being more stable the faster it's driven? and in rotating things in general being more stable the faster they're rotating.
Bicycles are complicated. There is more than one thing going on. You should not expect to find a single equation with a single unknown called "stability". Instead, you will find a collection of inter-related equations with a plethora of parameters.

Gyroscopic precession in particular is a bit simpler. You are probably concerned with torque-induced precession: https://en.wikipedia.org/wiki/Precession#Classical_(Newtonian)

The faster something is spinning, the less precession rate you get for a fixed input torque.
The faster a bike is moving, the more centripetal force you get for a fixed yaw rate.
 
  • Like
Likes russ_watters
Welcome to PF. :smile:

John3022 said:
Which equation is responsible for a bike being more stable the faster it's driven?
Which kind of stability? Stability when everything is mellow and changing slowly, or the loss of stability called a "tank slapper" at speed? (Full disclosure -- I saved my one and only life threatening tank slapper merging onto a freeway at high speed in an early morning commute, and installed a steering damper on my CBR600F4 the next week).

 
Thread 'Gauss' law seems to imply instantaneous electric field'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Hello! Let's say I have a cavity resonant at 10 GHz with a Q factor of 1000. Given the Lorentzian shape of the cavity, I can also drive the cavity at, say 100 MHz. Of course the response will be very very weak, but non-zero given that the Loretzian shape never really reaches zero. I am trying to understand how are the magnetic and electric field distributions of the field at 100 MHz relative to the ones at 10 GHz? In particular, if inside the cavity I have some structure, such as 2 plates...
Back
Top