Acceleration for a curved trajectory

[Jazzyrohan]

In feynman lectures on physics volume 1
Excerpt 11-6
I don't get how the equation \begin{equation*} \Delta v_\perp=v\,\Delta\theta \end{equation*} is found.

 

[haushofer]

Me neither, I don't have a copy of the Feynman lectures and don't have a clou what this all means.

 

[Jazzyrohan]

Me neither, I don't have a copy of the Feynman lectures and don't have a clou what this all means.

They are available online.

 

[Ibix]

It would be helpful to link, at least to section 11-6 even if you can't link to the equation: http://www.feynmanlectures.caltech.edu/I_11.html#Ch11-S6

$\sin\Delta\theta\simeq\Delta\theta$ if $\Delta\theta<<1$, is the relevant fact, I think. Then the result follows from figure 11-8.