Precession Period: Calculate Speed

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    Period Precession
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Homework Help Overview

The discussion revolves around calculating the speed of a wheel undergoing precession, with specific parameters such as diameter, mass, angular velocity, and the length of an attached rod. Participants are exploring the relationship between these variables and the period of the wheel's motion.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are examining the formula from Wikipedia and questioning the appropriate substitutions for variables such as radius and period. There is a focus on the conversion of units and the implications of these conversions on the calculated period.

Discussion Status

The discussion is actively exploring different interpretations of the problem, particularly regarding the correct application of the formula and unit conversions. Some participants have provided guidance on specific values and calculations, while others are questioning the assumptions made in the process.

Contextual Notes

There is a noted concern about the accuracy of the initial calculations and the potential confusion arising from unit conversions. Participants are also considering hypothetical scenarios where access to external resources is limited.

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Homework Statement


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Homework Equations


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this was a formula I just found on Wikipedia, but it seemed to be right for this problem.

The Attempt at a Solution



so we have the diameter of the of the wheel = 0.7 m

mass of wheel = 0.25 kg

distance of the rod attached = 0.2m

angular velocity of wheel converted to radians = 27 rad/s

moment of inertia for wheel = m r2

Ts = is the period of of the wheel

Tp is what we are solving for.
which comes out to be 639.7 seconds. if my math is correct. but this answer seems extremely unlikely

so the wheel moves to the left, but how can I figure out the speed at which it moves at?
 
Last edited:
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What are you substituting for r in the Wiki formula? What do you have for Ts?
 
haruspex said:
What are you substituting for r in the Wiki formula? What do you have for Ts?
r should be the length of the rod, which is 0.2m.

and Ts is 1/258 = 0.00387 seconds per revolution.

correct?
 
goonking said:
r should be the length of the rod, which is 0.2m.

and Ts is 1/258 = 0.00387 seconds per revolution.

correct?
The wheel's rotation rate is given as 258 revolutions per what?
 
haruspex said:
The wheel's rotation rate is given as 258 revolutions per what?
minutes, oh no! i forgot to convert
 
goonking said:
minutes, oh no! i forgot to convert

new answer comes out to be 10.7 seconds, which is sounds reasonable
 
goonking said:
new answer comes out to be 10.7 seconds, which is sounds reasonable
Yes, it does.
 
haruspex said:
Yes, it does.
ok, let's say i had no access to the internet, and I had no way of finding that formula, how would I then find the speed at which the wheel moves to the left?
 

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