1.At a factory, a noon whistle is sounding with a frequency of 477 Hz. As a car traveling at 84 km/h approaches the factory, the driver hears the whistle at frequency fi. After driving past the factory, the driver hears frequency ff. What is the change in frequency ff - fi heard by the driver? (Assume a temperature of 20° C.)

2. An ambulance traveling at 47 m/s approaches a car heading in the same direction at a speed of 36 m/s. The ambulance driver has a siren sounding at 600 Hz. At what frequency does the driver of the car hear the siren? (Assume a temperature of 20° C.)

3. A source and an observer are each traveling at 0.56 times the speed of sound. The source emits sound waves at 1.0 kHz. (a) Find the observed frequency if the source and observer are moving toward each other.

(b) Find the observed frequency if the source and observer are moving away from each other.

(c) Find the observed frequency if the source and observer are moving in the same direction.

 

What's a kilometer?

 

Its what everyone else but America uses.

 

Oh, okay...

What is this, "whistle?"

 

1. is delta(f) =-65.77 Hz.
workin on 2 now

 

2. is 794.79Hz

 

Just reading that made my brain hurt. If god wanted us to be able to do math, he would have given us more than 10 fingers & 12 toes. 1 KPH = 0.62137 MPH

 

#2 = 588.89Hz (i think...)

Scratch that - slightly wrong formula - my new answer is 619.884 Hz but that still is probably wrong :-D

 

ill check it in a sec

 

3A. 8333.333 Hz
B.471 Hz
C.1 kHz

Am i right with any of em?