Conservation of Angular Momentum of wheel

In summary: Ok, so I am trying to learn this on my own. Can you explain it to me now?Sure, let me try to explain it step by step:1. The spinning wheel has angular momentum, which means it is rotating around its center point (the axle) with a certain amount of energy and direction.2. When you start to turn left while holding onto the axle, the wheel wants to continue spinning in the same plane. This is due to the conservation of angular momentum, which states that the total angular momentum of a system remains constant unless acted upon by an external force.3. In order for the wheel to continue spinning in the same plane, the right side of the axle (which is moving towards you) needs to
  • #1
BIOPSYCH
11
0
1. You are walking holding on to the axle of a spinning bicycle wheel with one hand on either side of the wheel. The top part of the wheel is moving away from you and the bottom is moving toward you and the axle is horizontal. As you start to turn left, you feel
the right side of the axle

A. push on your right hand toward the left.
B. push on your right hand toward you.
C. pull on your right hand away from you.
D. push on your right hand vertically up.
E. push on your right hand vertically down.

I know this is a conservation of angular momentum problem and I believe the answer is not C because it wouldn't be pulling, it would be pushing. I also don't believe the answer is either D or E because it is not really a matter of vertical direction. To that end, I believe the answer is either A or B.

Is it A or B or neither? How do I logically defend my answer.
 
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  • #2
Welcome to PF!

Hi BIOPSYCH! Welcome to PF! :smile:

The https://www.physicsforums.com/library.php?do=view_item&itemid=313" is originally left or right (which?)

If you move very slightly anticlockwise (left), then the change in angular momentum is towards you or away from you (which?) …

so which way do you need to twist the axle to produce that change? :wink:
 
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  • #3


tiny-tim said:
Hi BIOPSYCH! Welcome to PF! :smile:

The https://www.physicsforums.com/library.php?do=view_item&itemid=313" is originally left or right (which?)

If you move very slightly anticlockwise (left), then the change in angular momentum is towards you or away from you (which?) …

so which way do you need to twist the axle to produce that change? :wink:

Does that mean that the answer I should be going with is A?
 
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  • #4
BIOPSYCH said:
Does that mean that the answer I should be going with is A?

No, it means that you should give logical reasons for your answer rather than making intelligent guesses. :wink:
 
  • #5
So, the angular momentum is originally to the right and if it changes slightly to the left, then the change is away from me. Is this the correct rationale to defend an answer of A.
 
  • #6
BIOPSYCH said:
So, the angular momentum is originally to the right and if it changes slightly to the left, then the change is away from me.

Isn't the angular momentum is originally to the left? :confused:
 
  • #7
tiny-tim said:
Isn't the angular momentum is originally to the left? :confused:

Yes, it is to the left, I typed it wrong.
 
  • #8
Upon closer consideration, I think the answer is B. Can someone please confirm this yes or no?
 
  • #9
Hi BIOPSYCH! :smile:

(just got up :zzz: …)
BIOPSYCH said:
… Is it A or B or neither? How do I logically defend my answer.

Yes, you wanted to be able to logically defend your answer.

But so far all you've done is make intelligent guesses which appear little more than random.

This randomness is … what's a good word? … enhanced by apparently typing "right" when you meant "left"! :rolleyes:

This is no way to practise for passing exams. :redface:
BIOPSYCH said:
Does that mean that the answer I should be going with is A?
BIOPSYCH said:
So, the angular momentum is originally to the right and if it changes slightly to the left, then the change is away from me. Is this the correct rationale to defend an answer of A.
BIOPSYCH said:
Yes, it is to the left, I typed it wrong.
BIOPSYCH said:
Upon closer consideration, I think the answer is B. Can someone please confirm this yes or no?

Now come on, it's a new day, you've had some sleep, do what you originally set out to do, and set out your answer logically, step by step, missing nothing out.

The we can check your logic, and you'll be sure that you can tackle similar problems on your own in the future. :smile:
 
  • #10
1. B -- The spinning wheel wants to continue to play on the same plane so in order for this to happen the right side would need to come towards you.

This is the best I am coming up with. Is this correct?
 
  • #11
BIOPSYCH said:
1. B -- The spinning wheel wants to continue to play on the same plane so in order for this to happen the right side would need to come towards you.

I don't understand it. :confused:
 
  • #12
Ok, so I am trying to learn this on my own. Can you explain it to me now?
 

1. What is the conservation of angular momentum of a wheel?

The conservation of angular momentum of a wheel is a physical law that states that the angular momentum of a wheel remains constant unless an external torque acts upon it. This means that the rotational motion of a wheel will stay the same unless an external force is applied to change it.

2. How does the conservation of angular momentum apply to a spinning wheel?

The conservation of angular momentum applies to a spinning wheel by stating that the angular momentum will remain constant as long as no external forces, such as friction or gravity, act upon it. This means that the wheel will continue to spin at the same speed and direction unless an external force is applied.

3. Why is the conservation of angular momentum important in understanding the motion of a wheel?

The conservation of angular momentum is important in understanding the motion of a wheel because it helps explain why a wheel will continue to spin at a constant rate even when no external forces are acting upon it. This is essential in understanding the behavior of rotating objects and can be applied to various real-world situations.

4. How does the conservation of angular momentum affect the stability of a spinning wheel?

The conservation of angular momentum affects the stability of a spinning wheel by keeping it in a state of rotational equilibrium. This means that the wheel will continue to spin at a constant rate and direction, making it stable and resistant to any external forces that may try to alter its motion.

5. Can the conservation of angular momentum be violated?

No, the conservation of angular momentum is a fundamental law of physics and cannot be violated. However, in some cases, it may appear to be violated due to external forces that are not accounted for or are too small to be measured. Overall, the conservation of angular momentum is a reliable principle that holds true in many physical systems.

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