# Period of precession

#### goonking

1. Homework Statement 2. Homework Equations this was a formula I just found on Wikipedia, but it seemed to be right for this problem.

3. 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

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?

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#### haruspex

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What are you substituting for r in the Wiki formula? What do you have for Ts?

#### goonking

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?

#### haruspex

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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?

#### goonking

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

#### goonking

minutes, oh no! i forgot to convert
new answer comes out to be 10.7 seconds, which is sounds reasonable

#### haruspex

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new answer comes out to be 10.7 seconds, which is sounds reasonable
Yes, it does.

#### goonking

Yes, it does.
ok, lets 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?