Finding Moment of Inertia of a wheel experimentally

AI Thread Summary
The discussion focuses on developing a simple method to experimentally determine the moment of inertia (MOI) of real wheels, particularly for bicycles and vehicles. The proposed formula for calculating MOI involves measuring the time it takes for a free weight to fall while accelerating the wheel, with the formula being MOI = ((g t1^2 / 2H) - 1) M R^2. The contributor seeks confirmation of this formula and acknowledges the potential impact of friction on the results. They also mention the possibility of using energy equations as an alternative method for verification. The conversation highlights the importance of accurate measurements and considerations in experimental physics.
Loudhvx
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Hello all, and forgive me if I'm making newbie mistakes as I haven't posted here much.

I realize this appears to be a homework assignment, but it is not. I am trying to develop an easy method for determining the actual moment of inertia for real wheels, for bicycles and other vehicles. I googled the topic and many related results came up, but not explicitly for finding the MOI with a simple formula.

I believe I have the correct formula, but I need confirmation from more knowledgeable people. I made a pdf file summarizing the problem including a drawing. I hope the link works.

https://s3.amazonaws.com/loudfiles/MomentOfInertiaWheel_TEMP.pdf

All of the quantities are constant, as in not varying with time.
I neglect friction, but realize it can be a significant factor on a real wheel if not dealt with properly.

In case the link doesn't work, here is what I have:
A wheel of radius R is mounted with its axle horizontal.
A string is attached, and wrapped around the perimeter of the wheel (at radius R distance from the center).
The free end of the string is attached to a free-weight of mass M.
The free weight is allowed to fall a distance H, vertically, which accelerates the wheel.
The time it takes the weight to travel H is time t1.
g is the acceleration of gravity.

The MOI = ( (g t12 / 2 H) - 1 ) M R2

Can someone please confirm that for me? Thank you very much for your time.
 
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I forgot this can probably also be done using energy equations, so I forgive me, as that would have been a way I could check my results. If someone has that solution handy, that would be great as well. I will attempt that, but it will likely take me some time to brush up on those equations/concepts.
 
Perhaps see ...
 
Thanks. That does at least confirm the relationship of I to a.
 
You might be able to devise a way to take into account friction in your calculation of MOI.
 

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