## Essential University Physics: Volume 1 (4th Edition) Clone

$.0153 \ m/s$
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: $\Delta f v - \Delta f u =2uf$ $\Delta f v = \Delta f u +2uf$ $\Delta f v =u( \Delta f +2f)$ $u = \frac{\Delta f v }{\Delta f +2f}$ $u = \frac{(100)(1540)}{ 100 +2(5,000,000)}=.0153 \ m/s$