Question 604Navigation General

70% to pass

The spin axis of a gyroscope tends to remain fixed in space in the direction in which it is started. How does this gyroscope become north seeking so that it can be used as a compass?

A By starting the compass with the spin axis in a north/south position
B The rotation of the Earth (Earth rate) automatically aligns the gyroscope with north, except for speed errors
C By mechanically or electrically applying forces to precess the gyroscope
D By taking advantage of the property of gyroscopic inertia
AI Explanation

The correct answer is C) By mechanically or electrically applying forces to precess the gyroscope. A gyroscope's spin axis tends to remain fixed in space, but this alone does not make it "north seeking" for use as a compass. To align the gyroscope with north, forces must be applied to precess or rotate the gyroscope's spin axis until it points to true north. This can be done mechanically, such as with a gimbaled mount, or electrically, by applying current to torque motors that induce precession. The other answer choices are incorrect because they do not fully explain how a gyroscope is made to point north for compass use.

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Official Resources
USCG Navigation Rules (COLREGS) 33 CFR Navigation Rules USCG National Maritime Center
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