What frequency is received by the ambulance after reflecting from a wall near the person watching the oncoming ambulance (as in the previous problem). the ambulance is moving at 104 km/h and emitting a steady 821-hz sound from its siren? the speed of sound on this day is 345 m/s.

f=896Hz

Explanation:

Given data

Vs(speed of the ambulance)={(104 km/h)*(1000m*(1 h/3600)}=28.9m/s

f(frequency of the ambulance siren)=821 Hz

v(speed of sound)=345 m/s

Vo(speed of the observer)=0 m/s

To find

f(The ambulance is approaching the person)

Solution

From Doppler effect

As the ambulance approaches the we assign a positive sign for speed "vs" of the ambulance

So

Substitute the values from given data

the moving of the box is a result of centripetal force. think of that  as a car or a truck in this case creates a turn, the force of friction performing upon the turned wheels of the car runs centripetal force obligatory for circular motion for the things inside it.