# Why is a gyroscope's precession fastest at 45 degrees?

## Main Question or Discussion Point

I did an experiment in which I varied the starting angle of elevation of a gyroscope. I noticed that at 45 degrees, the precessional period (amount of time to perform one spin) is the lowest, while at 0 degrees and 75 degrees, the precessional period is higher. If I plotted this on a graph, it looks somewhat like half a sinusoidal curve, with 45 degrees being the minimum.

Keep in mind that the starting angular frequency of the rotor/wheel in the gyroscope is always the same in the beginning.

I just want to know why a gyroscope tends to spin faster at 45 degrees.

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Is there a centrifugal force that acts on the rotor? I found on a website:

http://www.gyroscopes.org/forum/questions.asp?id=1533

"The centrifugal force when the arm is at 45 degrees above or below horizontal would be about 70.7 percent of what it is at horizontal. Of course the centrifugal force would vary for every angle above or below horizontal for a fixed precession rpm. If you plotted the calculated centrifugal force for varying angles at a fixed precession rpm, the graph would be 1/2 a sinusoid."

Can anyone verify this? I didn't think centrifugal forces existed.