Why do moving objects stay balanced

  • Context: High School 
  • Thread starter Thread starter yup790
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the stability of moving objects, particularly focusing on why gyroscopes and objects moving in a straight line do not fall over. It explores concepts related to gyroscopic effects, torque, angular momentum, and the stability of bicycles with different wheel designs.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions why gyroscopes or objects moving in a straight line do not fall over, suggesting a simple explanation is needed.
  • Another participant states that whether an object falls over depends on various factors, using the example of an ice skate to illustrate instability in non-rolling objects.
  • A claim is made that rolling objects do not fall over due to gyroscopic effects, which involve torque and angular momentum.
  • One participant argues that a bicycle could be stable with non-rolling curved ice skate blades due to steering geometry, challenging the necessity of gyroscopic effects for stability.
  • Another participant counters this claim, asserting that a bicycle's stability is primarily due to the rotation of its wheels rather than steering geometry.
  • A later reply references previous discussions on the forum regarding bicycles without gyroscopic effects that remain upright due to steering geometry, suggesting that this has been empirically demonstrated.
  • A participant provides a link to a Physics Today paper discussing bicycle stability, indicating ongoing research in the area.

Areas of Agreement / Disagreement

Participants express differing views on the factors contributing to the stability of moving objects, particularly bicycles. There is no consensus on whether gyroscopic effects or steering geometry is the primary reason for stability.

Contextual Notes

Some claims rely on specific definitions of stability and may depend on the context of motion (e.g., rolling vs. non-rolling). The discussion includes references to previous threads and empirical studies, but the details of those studies are not fully explored within this thread.

yup790
Messages
21
Reaction score
0
Why do gyrascopes or things moving in a stright line not fall over. Probably a simple answer but i cannot work it out.
 
Physics news on Phys.org
Whether a thing moving in a straight line falls over or not depends on a number of factors. Try to send a single ice skate along the surface some time. You'll see that it does fall over quite easily. Rolling things don't fall over because of gyroscopic effect. And gyroscopic effect has to do with torque and angular momentum. If you look up gyroscope on Wikipedia, it will get you started. If you'll have specific questions later on, ask them.
 
K^2 said:
Try to send a single ice skate along the surface some time.
It would be possible to replace the wheels of a bicycle with large curved ice skate like blades (non-rolling) and because of the steering geometry, the bike would be stable, without any gyroscopic effects.
 
Yes. I never insisted that gyroscopic effect is the only way to achieve stability. Not sure where you got that from. Just wanted to show a clear example of a situation where the object is most certainly unstable, and a lone skate definitely qualifies.
 
rcgldr said:
It would be possible to replace the wheels of a bicycle with large curved ice skate like blades (non-rolling) and because of the steering geometry, the bike would be stable, without any gyroscopic effects.
No, that is not true. A bicycle is stable precisely because of the rotation of the wheels, not any "steering geometry".
 
HallsofIvy said:
No, that is not true. A bicycle is stable precisely because of the rotation of the wheels, not any "steering geometry".

This has been discussed at length on Physics Forums. Search previous threads. Research groups have literally constructed bikes without gyroscopic effects and they still stay upright when in motion, even without a human pilot, because of the steering geometry.

See this article for instance.
 

Similar threads

High School Lever balancing physics (video game design)
  • · Replies 18 ·
Replies
18
Views
3K
High School How is an unstable object balanced?
  • · Replies 15 ·
Replies
15
Views
2K
High School Does acceleration affect impact energy vs constant velocity?
  • · Replies 46 ·
2
Replies
46
Views
6K
High School Do Objects in Free Fall Encounter Air Resistance?
  • · Replies 10 ·
Replies
10
Views
2K
High School Curious about the work - energy theorem
  • · Replies 8 ·
Replies
8
Views
2K
High School Curious about Work and Energy Consumption
  • · Replies 8 ·
Replies
8
Views
2K
High School Why does a spinning top balance better when it is spinning?
  • · Replies 12 ·
Replies
12
Views
2K
High School What forces are required to tumble a block?
  • · Replies 16 ·
Replies
16
Views
2K
Undergrad Normal force and details of the Earth holding up an object
  • · Replies 12 ·
Replies
12
Views
2K
High School Help with science experiment magnets/force/acceleration/speed
  • · Replies 6 ·
Replies
6
Views
2K