# What is Gyroscopic Couple?

Question asked by EDDY in #Coffee Room on Jul 28, 2009

EDDY · Jul 28, 2009

Rank D2 - MASTER

Can some explain me the concept of gyroscopic couple and is there any good project on it, plz help me with some examples in general life??????
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#Coffee Room

Rohan_sK · Jul 29, 2009

Rank C2 - EXPERT

Gyroscopic Couple is what a biker experiences while countering a turn either in the left or the right direction and this is what helps the rider to keep the bike upright.

Suppose that a wheel rotates around an axis perpendicular to the page with an angular veolocity ω. Then the angular momentum is given by Iω and its direction will be a vector along the axis.

If the axis of rotatoion undergoes an angular displacement of δθ in time δt resulting in an precession velocity of φ, then the new angular momentum will be Iω in magnitude and the vector will be displaced by δθ wrt Iω.

The vectors representing Iω be called ‘oa’ and that of Iφ be called ‘ob’.

Hence the rate of change of angular momentum is called the Gyroscopic Couple ζ .

Hence the vector ‘ab’ is the change in the angular momentum in the interval δt,

Thus,

Gyroscopic couple ζ = ab/ δt

= Iω. Δθ/ δt

ζ = Iω. φ

This is the gyroscopic couple acting will be in the sense of rotation along ab and will be perpendicular to both ω and φ.

Hope this gives you a basic understanding of the gyroscopic couple

Suppose that a wheel rotates around an axis perpendicular to the page with an angular veolocity ω. Then the angular momentum is given by Iω and its direction will be a vector along the axis.

If the axis of rotatoion undergoes an angular displacement of δθ in time δt resulting in an precession velocity of φ, then the new angular momentum will be Iω in magnitude and the vector will be displaced by δθ wrt Iω.

The vectors representing Iω be called ‘oa’ and that of Iφ be called ‘ob’.

Hence the rate of change of angular momentum is called the Gyroscopic Couple ζ .

Hence the vector ‘ab’ is the change in the angular momentum in the interval δt,

Thus,

Gyroscopic couple ζ = ab/ δt

= Iω. Δθ/ δt

ζ = Iω. φ

This is the gyroscopic couple acting will be in the sense of rotation along ab and will be perpendicular to both ω and φ.

Hope this gives you a basic understanding of the gyroscopic couple

Ankita Katdare · Oct 30, 2017

Rank A1 - PRO

That's a really fantastic explanation by @Rohan_sK Do check out this video about Gyroscopic Precession -

ANBALAGAN PONNUSWAMY · Oct 14, 2018

Rank E1 - BEGINNER

Very simple and easy understanding answer, thanks a lot.