- 64

- 1

The attitude can be represented as ##\boldsymbol\gamma=\phi\hat{\boldsymbol e}##, where ##\hat{\boldsymbol e}## is the

*principal axis*of the rotation. In a course I'm watching online, the professor computes the derivative of ##\boldsymbol\gamma## as follows:$$

\dot{\boldsymbol\gamma} = \dot\phi \hat{\boldsymbol e}

$$

Wouldn't that be correct only for a fixed ##\hat{\boldsymbol e}##? Shouldn't we assume ##\hat{\boldsymbol e}## is changing in time as well?