Chapter 11, Problem 71P

& Detecting speed of baseball A Doppler speed meter operating at exactly $\text{1}\text{.02**\#x00A0;}\times {\text{ 10}}^{\text{5}}$

Hz emits sound waves and detects the same waves after they are reflected from a baseball thrown by the pitcher. The receiver “mixes" the reflected wave with a small amount of the emitted wave and measures a beat frequency of $\text{0}\text{.30 }\times {\text{ 10}}^{\text{5}}$

Hz How fast is the ball moving?