A sample of a synthetic tissue-mimicking polymer, used for calibrating medical ultrasound transducers, has a volume of 5.0 cm3 and a mass of 5.25 g. The speed of ultrasound in this polymer sample is 1600 m s-1. What is the acoustic impedance of the polymer?
1.68×103 kg m−2 s−11.68 \times 10^3\text{ kg m}^{-2}\text{ s}^{-1}1.68×103 kg m−2 s−1
1.68×105 kg m−2 s−11.68 \times 10^5\text{ kg m}^{-2}\text{ s}^{-1}1.68×105 kg m−2 s−1
1.68×109 kg m−2 s−11.68 \times 10^9\text{ kg m}^{-2}\text{ s}^{-1}1.68×109 kg m−2 s−1
1.68×106 kg m−2 s−11.68 \times 10^6\text{ kg m}^{-2}\text{ s}^{-1}1.68×106 kg m−2 s−1
