# Gyroscope moment of Inertia

1. Sep 9, 2011

### Daniiel

Hey

I just finished an experiment in my physics lab where we examined the precession and nutation of a gyroscope.

The gyroscope was built with a shaft which had a pivot in the middle, on one end of the shaft the large spinning disc was placed and on the left side of the shaft counterweights were placed.

Torque was applied on the side of the large spinning disc, firstly the shaft was kept horizontal and several measurements were made (the angular precession frequency and the angular frequency of the spinning disc) then a relationship was developed and compared to a formula we were provided. This formula was wpr = T/(Ix wx)
Where T is torque r x F, Wpr the precession frequency, Wx the spin frequency and Ix the moment of inertia about the x axis which was 0.5MR2 where M is the mass of the disc, R is it's radius.

Our results fit well this the equation provided and everything seemed correct.

We then examined the effect of changing the angle of inclination, so took the measurements again with the disc raised at various angles. The results obtained were not consistent with the forumla provided.

My question is, does the moment of inertia about the x axis change when the disc is lifted, and if so does it decrease?

I would think it does change since at the horizontal everything is at its furthest apart positions, then when the disc is lifted above the horizontal everything moves closer towards the axis of the pivot, kind of hard to explain that sorry.

Here's a terribly drawn picture of the apparatus:
http://img198.imageshack.us/img198/4884/gyroscope.jpg [Broken]

Daniel
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited by a moderator: May 5, 2017
2. Sep 9, 2011

### Spinnor

I'm sure you took into account that rxF is not a constant?

3. Sep 9, 2011

### Daniiel

Yea we did,

Do you think its correct to think that Ix changes?