a car makes sound as it moves toward a stationary observer. what best describes the sound wave heard by the…

a car makes sound as it moves toward a stationary observer. what best describes the sound wave heard by the observer compared with the sound heard by the cars driver?\no higher frequency; shorter wavelength\no higher frequency; longer wavelength\no lower frequency; shorter wavelength\no lower frequency; longer wavelength
Answer
Answer:
higher frequency; shorter wavelength
Explanation:
Step1: Recall Doppler - effect concept
When a source (car) moves towards a stationary observer, the Doppler - effect occurs for sound waves.
Step2: Understand frequency change
The relative motion causes the observer to receive more wave - fronts per second, increasing the frequency.
Step3: Analyze wavelength change
Since the speed of sound $v = f\lambda$ (where $v$ is speed, $f$ is frequency, and $\lambda$ is wavelength) and the speed of sound in the medium is constant, when $f$ increases, $\lambda=\frac{v}{f}$ decreases.