A car travelling at 90 km/hr sounds it horn as it approaches a stationary cyclist.if the car horn is at 512 Hz and temperature of air is 10 degree centigrade, what is the frequency of the sound waves reaching the cyclist as car approaches.

f = fo v/v-vs

You'll have to look up the speed of sound at 10o, and don't forget to convert to m/s

To find the frequency of the sound waves reaching the cyclist as the car approaches, we first need to understand the concept of the Doppler effect. The Doppler effect describes the apparent change in frequency of a wave (sound, light, etc.) when the source of the wave and the observer are in relative motion.

In this case, the observer is the cyclist and the source is the car horn. The car horn emits sound waves at a certain frequency, and due to the relative motion between the car and the cyclist, the frequency of the sound waves will appear different to the cyclist.

The formula for calculating the observed frequency (f') due to the Doppler effect is:

f' = f (v + vo) / (v - vs)

where:
f = frequency of the source (car horn) at rest
v = speed of sound in air
vo = velocity of the observer (cyclist)
vs = velocity of the source (car)

Given:
f = 512 Hz (frequency of the car horn at rest)
v = speed of sound in air (which can be approximated as 343 m/s at 10 degrees Celsius)
vo = velocity of the observer (cyclist) = 0 km/hr (stationary)
vs = velocity of the source (car) = 90 km/hr (approaching the cyclist)

Now, we need to convert the velocities from km/hr to m/s.

vo = 0 km/hr = 0 m/s
vs = 90 km/hr = 25 m/s (90/3.6)

Substituting the values into the formula, we have:

f' = 512 (343 + 0) / (343 - 25)

Simplifying the equation:

f' = 512 * 343 / 318

Calculating:

f' ≈ 552.83 Hz

Therefore, the frequency of the sound waves reaching the cyclist as the car approaches is approximately 552.83 Hz.