Una sirena que emite un sonido de f=100Hz se mueve alejandose de un observador en reposo y dirigiendose hacia un acantilado con velocidad constante de v1=20 m/s.

Given that,

Frequency = 100 Hz

Velocity = 20 m/s

Suppose, Determinar la diferencia de  frecuencia entre la onda que recibe el observador directamente de la sirena y la onda que le llega reflejada  en el acantilado.

We need to calculate the frequency heard by the observer directly from source

Using formula of frequency

Where, v = speed of sound

= speed of source

f = frequency of source

Put the value into the formula

We need to calculate the frequency heard by the observer coming after reflection from cliff

Using formula of frequency

Put the value into the formula

We need to calculate the difference of  frequency

Using formula for difference of  frequency

Put the value into the formula

Hence, The difference of frequency is 11.85 Hz.

i believe the answer is a

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary