In section 11.5 on page 271 in figure 11.28 and the associated discussion: The physics here is correct, but the terminology is somewhat off-putting.
In this situation the "rotation axis" is a misnomer, since precisely nothing is rotating. In many branches of physics and engineering, the point in question is called the reference point or the datum.
Suggestion: It is well worth emphasizing that the datum does not need to coincide with the axis of rotation (if any), does not need to coincide with the CM. You can choose any datum you like. For example, when computing the weight and balance for an aircraft, the datum used by the Pilot's Operating Handbook is typically nowhere near the CM. Also, when the airplane is turning, neither the POH datum nor the CM is anywhere near the center of rotation.
In section 11.5 on page 271 in figure 11.28 and the associated discussion: The physics here is correct, but the terminology is somewhat off-putting.
In this situation the "rotation axis" is a misnomer, since precisely nothing is rotating. In many branches of physics and engineering, the point in question is called the reference point or the datum.
Suggestion: It is well worth emphasizing that the datum does not need to coincide with the axis of rotation (if any), does not need to coincide with the CM. You can choose any datum you like. For example, when computing the weight and balance for an aircraft, the datum used by the Pilot's Operating Handbook is typically nowhere near the CM. Also, when the airplane is turning, neither the POH datum nor the CM is anywhere near the center of rotation.