Welcome to Physics Forums.Kinar said:Homework Statement
A policeman detects a drop of 10% in the pitch of the horn of a motor car as it crosses him. If the velocity of sound is 330ms^-1, calculate the speed of the car.
Homework Equations
f2 = f1 [v - v(listener)]/[v - v(source)]
where f2 = apparent frequency
f1 = true frequency
The Attempt at a Solution
I'm confused about how the car crosses him. Please help.
The Doppler Effect of Sound refers to the change in frequency of a sound wave as the source of the sound moves towards or away from an observer. This results in a perceived change in pitch of the sound.
The Doppler Effect of Sound is based on the principle that the distance between the source of the sound and the observer affects the perceived frequency of the sound. When the source moves towards the observer, the wavelength of the sound waves becomes shorter and the frequency increases, resulting in a higher pitch. Conversely, when the source moves away from the observer, the wavelength becomes longer and the frequency decreases, resulting in a lower pitch.
Some common examples of the Doppler Effect of Sound include the change in pitch of a siren as an ambulance passes by, the change in pitch of a train horn as it approaches and then moves away, and the change in pitch of a car horn as a car drives by.
The Doppler Effect of Sound is used in various scientific and technological applications, such as in meteorology to measure the speed and direction of moving storms, in astronomy to determine the speed and direction of celestial objects, and in sonar technology to detect and locate objects underwater.
The perceived Doppler Effect of Sound can be affected by various factors, including the relative speed and direction of the sound source and the observer, the frequency and wavelength of the sound waves, and any obstructions or reflections in the environment that may alter the sound waves.