I Conservation of angular momentum -- spinning a bicycle wheel in space

AI Thread Summary
In a frictionless environment, a bicycle wheel in space will not stop rotating unless acted upon by an external force. The conservation of angular momentum remains intact as the wheel's friction with the axle causes both to eventually rotate at the same rate, rather than stopping completely. If the wheel is mounted on a non-rotating bike, the torque will cause the bike to rotate, conserving the total angular momentum of the system. Thus, the initial assertion that angular momentum is violated is incorrect. The system continues to exhibit conservation principles as long as no external forces intervene.
abdossamad2003
Messages
68
Reaction score
4
Suppose we have a rotating body like a bicycle wheel in space away from gravity. This body stops after a while due to friction between the wheel and wheel axles. Is not the conservation of angular momentum violated?
 
Physics news on Phys.org
If it's just the wheel, then there's no axle exerting friction and the wheel will rotate without slowing forever. If it is mounted on a non-rotating bike, then the bike will take up the torque and begin rotating, conserving angular momentum.
 
Reply
  • Like
Likes nasu and PeroK
abdossamad2003 said:
Suppose we have a rotating body like a bicycle wheel in space away from gravity. This body stops after a while due to friction between the wheel and wheel axles. Is not the conservation of angular momentum violated?
You are wrong to say that the body stops. As per @Halc's answer, the wheel slows and the axle spins up until both are rotating at the same rate. Then the wheel and axle continue to spin eternally, at rest with respect to each other.
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »

Thread 'Newton's first law?'

Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
View full post »
Thread 'Beam on an inclined plane'

Thread 'Beam on an inclined plane'

Hello! I have a question regarding a beam on an inclined plane. I was considering a beam resting on two supports attached to an inclined plane. I was almost sure that the lower support must be more loaded. My imagination about this problem is shown in the picture below. Here is how I wrote the condition of equilibrium forces: $$ \begin{cases} F_{g\parallel}=F_{t1}+F_{t2}, \\ F_{g\perp}=F_{r1}+F_{r2} \end{cases}. $$ On the other hand...
View full post »

Similar threads

Spinning Bike Wheel Example, how is angular momentum conserved?
Replies
9
Views
5K
Conceptual questions about Angular Momentum Conservation and torque
Replies
2
Views
2K
Conservation of Angular Momentum and a Spinning Bicycle Wheel
Replies
5
Views
3K
I I never fully understood gyroscopic precession - toppling gyroscopes
Replies
10
Views
375
B The physics of flywheel launchers (like tennis ball shooters)
2
Replies
60
Views
4K
Conservation of Angular Mometum for a Car/Earth System
Replies
20
Views
2K
I Conservation of Angular Momentum vs a gyro at the North Pole
Replies
16
Views
960
ABS system on a two-wheeled vehicle - Conservation of Angular Momentun
Replies
7
Views
1K
How Does Angular Momentum Apply to Earth and Spinning Bike Wheels?
Replies
36
Views
4K
I Conservation of angular momentum during collisions
Replies
3
Views
3K

Hot Threads

Recent Insights

Back
Top