On page 255 the title of section 11.1 is Circular motion at constant speed
The discussion on age 256 doesn't make much sense. It refers to «the» speed of an «object». It might make sense if it referred to a particle, but here it speaks of objects, which in this context are extended rigid-body objects, not pointlike particles. Such an object does not have a single well-defined velocity or speed.
Suggestion:
I see two possibilities; pick one:
(Less likely guess)-- It may be that the intent was to refer to the speed of the object's center of mass.
(My best guess)-- I suspect that the intent was to describe an extended object undergoing circular motion at constant angular RATE around a fixed center. If so, the passage will need to be extensively rewritten to communicate this idea. The notion of rigid-body motion as discussed in item #204 may help here, including the idea of fixed distances from a fixed center.
In any case, angular RATE should not be called speed. You can call it angular velocity or even angular speed ... but plain old «speed» is not a viable option. Speed and angular speed may be analogous, but they are not the same thing, as you can see from the definition of speed on page 49.
The same issue shows up in the chapter summary (aka «glossary») on page 280.
On page 255 the title of section 11.1 is
Circular motion at constant speedThe discussion on age 256 doesn't make much sense. It refers to «the» speed of an «object». It might make sense if it referred to a particle, but here it speaks of objects, which in this context are extended rigid-body objects, not pointlike particles. Such an object does not have a single well-defined velocity or speed.
Suggestion:
I see two possibilities; pick one:
In any case, angular RATE should not be called speed. You can call it angular velocity or even angular speed ... but plain old «speed» is not a viable option. Speed and angular speed may be analogous, but they are not the same thing, as you can see from the definition of
speedon page 49.The same issue shows up in the chapter summary (aka «glossary») on page 280.