In section 11.5 in exercise 11.6 on page 273 everything it says about "THE" angular momentum would be true if restricted to the angular momentum about the CM ... but not true otherwise. Suggestion: It would be good to make this explicit.
This is a continuation of the point made in connection with figure 11.28 on page 271. You can choose any datum you like, and measure angular momentum from there.
A uniform gravitational field can be treated as equivalent to a single force acting on the CM. So the gravitational force has no lever arm about the CM. This is the correct explanation of why the total angular momentum of the diver about the CM remains unchanged (neglecting aerodynamics). Suggestion: It would be good to make this explicit.
This is closely related to item #119.
In section 11.5 in exercise 11.6 on page 273 everything it says about "THE" angular momentum would be true if restricted to the angular momentum about the CM ... but not true otherwise. Suggestion: It would be good to make this explicit.
This is a continuation of the point made in connection with figure 11.28 on page 271. You can choose any datum you like, and measure angular momentum from there.
A uniform gravitational field can be treated as equivalent to a single force acting on the CM. So the gravitational force has no lever arm about the CM. This is the correct explanation of why the total angular momentum of the diver about the CM remains unchanged (neglecting aerodynamics). Suggestion: It would be good to make this explicit.