Why does a bicycle wheel precess when suspended from a string?

In summary, the reason for the precession of a bicycle wheel suspended by a string from a rigid support is due to the two forces acting on the system - the downward force of gravity at the center of mass of the wheel and the upward tension in the string. The axle of the wheel remains horizontal because these two forces cancel each other out, despite their different lines of action. The lines of action only affect the net torque, not the net force. This clarification was appreciated by the speaker.
  • #1
Amith2006
427
2
Almost everything is clear to me as far as the reason for the precession of a bicycle wheel suspended by a string from a rigid support is concerned. But I don't understand one thing about it. There are 2 forces acting on the system- one is the downward force of gravity at the center of mass of the wheel and the other is the tension in the string acting in the upward direction. It is said that the axle of the wheel manages to remain horizontal as the 2 forces get cancelled. How is it possible when the lines of action of the 2 forces are different?
 
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  • #2
The lines of action affect the net torque, but not the net force.
 
  • #3
You are right! Thanx.
 

1. What is bicycle wheel precession?

Bicycle wheel precession is the phenomenon where a spinning bicycle wheel will automatically turn in the direction of the applied force. This is due to the conservation of angular momentum.

2. What causes bicycle wheel precession?

Bicycle wheel precession is caused by the torque applied to the wheel by the force of gravity acting on the bike and rider. As the bike and rider lean to one side, there is a torque created that causes the wheel to turn in the direction of the lean.

3. How does bicycle wheel precession affect riding?

Bicycle wheel precession can affect riding by causing the bike to turn in the direction of the applied force, which can be counterintuitive for new riders. It can also affect stability and balance, making it important for riders to understand and anticipate this phenomenon when riding.

4. Can bicycle wheel precession be used to turn while riding?

Yes, bicycle wheel precession can be used to turn while riding by leaning the bike and rider in the desired direction. This will create a torque on the wheel, causing it to turn and steer the bike in that direction.

5. How does the speed of the bicycle affect wheel precession?

The speed of the bicycle does not significantly affect bicycle wheel precession. However, higher speeds may require more force to create enough torque for the wheel to turn, making it more noticeable at faster speeds.

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