To Clear Things Up

I have made a mistake in the post "I Don't Know..." dated 12 Dec 2017, in the expression

$P=\cfrac{8^3}{18}{\pi^2}∗f^2∗m_ac^2=1∗\cfrac{4}{3}\pi∗f^3∗m_ac^2$

It should be

$P=\cfrac{8^3}{18}{\pi^2}∗f^2∗m_ac^2=1∗\cfrac{3}{4\pi}∗f^3∗m_ac^2$

where the $RHS$ is divided by a spherical volume to obtain energy per unit volume.  The expression leads to,

$f=\cfrac{4*8^3}{3*18}\pi^3=1175.94 Hz$

The previous result,

$f=\cfrac{8^3}{24}\pi=67.02\,Hz$

is not valid.

Sorry...