Question

The positive sign is used to determine the gyroscope couple in which of the following cases?

(a) When the wheels and rotating parts of the engine rotate in the same direction

(b) When the wheels and rotating parts of the engine rotate in the opposite direction

(c) When the precession is clockwise

(d) When the precession is anticlockwise

The question was asked in an international level competition.

Question is taken from Stability of a Four Wheel drive Moving in a Curved Path topic in portion Gyroscopic Couple and Precessional Motion of Machine Dynamics

Answer 1

Right option is (c) When the precession is clockwise

Explanation: The positive sign is used when the wheels and rotating parts of the engine rotate in the same direction. If the rotating parts of the engine revolve in opposite direction, then negative sign is used.