Answer
$.0153 \ m/s$
Work Step by Step
We use equation 14.16, which involves a Doppler shift for a moving observer, to find:
$f'=f(1\pm\frac{u}{v})$
Considering the second shift, this equation becomes:
$\Delta f = \frac{2 uf }{v-u}$
We know that the speed of sound in a human body, in this case v in the equation, is $1540 \ m/s$. Thus, we find:
$\Delta f v - \Delta f u =2uf$
$\Delta f v = \Delta f u +2uf$
$\Delta f v =u( \Delta f +2f)$
$u = \frac{\Delta f v }{\Delta f +2f}$
$u = \frac{(100)(1540)}{ 100 +2(5,000,000)}=.0153 \ m/s$
