Conservation of Angular Momentum of wheel

AI Thread Summary
The discussion revolves around the conservation of angular momentum as it relates to a spinning bicycle wheel. Participants debate whether the force felt on the right hand when turning left is a push toward the left (A) or toward the person (B). Initial confusion about the direction of angular momentum leads to a clarification that it is initially to the left. Ultimately, the consensus leans toward option B, where the right side of the axle pushes toward the person as they turn left. The emphasis is on logically defending the answer rather than making random guesses.
BIOPSYCH
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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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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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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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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:
 
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:
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:
 
tiny-tim said:
Isn't the angular momentum is originally to the left? :confused:

Yes, it is to the left, I typed it wrong.
 
Upon closer consideration, I think the answer is B. Can someone please confirm this yes or no?
 
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?
 
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