I am reading this book: "Flight Dynamic Principles" by Cook, second edition. You can read it here: https://aerocastle.files.wordpress.com/2012/04/flightdynamicsprinciples.pdf
First, go to the page 76, read the sentence:
Further, the only significant higher order derivative terms commonly encountered are those involving $\dot w$.
Why is the only $\dot w$ involved here? the $\dot u$ and $\dot v$ have the same roles, huh??
Second, same page 76, section 4.2.3, the sentence:
The assumptions applied to the aerodynamic terms are also applied to the control terms thus, for example, the pitching moment due to aerodynamic controls may be expressed.
And you can see the equation (4.32)
it is totally different from aerodynamics terms equation..why is that?. Why are moments not dependent u, v, w, and p, q, r like aerodynamics terms.
Lastly, look at the example 4.2 at page 80, what is the meaning of this example? where do the values of dimensionless longitudinal derivatives at page 81 come from? What are they? The book said seeing the appendix 2 at page 413. Now go to the page 413, where do these multipliers come from?