Physics

Problem

An ultrasound pulse is sent into a steel rod. The echo from a flaw inside the rod returns to the detector after

1.6\,\text{ms}

. If the speed of sound in steel is

5\,000\,\text{m/s}

, the depth of the flaw below the rod surface is a)

8\,\text{m}

16\,\text{m}

4\,\text{m}

2\,\text{m}