Two police cars have identical sirens that produce sound of ...

[Ebrown]

Two police cars have identical sirens that produce sound of frequency of 570 Hz. A stationary listener is standing between two cars.
 
  One car is parked and the other is approaching the listener and both have their sirens on. The listener measures 9.0 beats per second. Find the speed of the approaching police car. The speed of sound is 340 m/s.

Question 2

A violin with string length 32 cm and string density resonates in its fundamental with the first overtone of a 2.0-m organ pipe with one end closed and one end open. What is the tension in the string if the speed of sound in air is 344 m/s?
 
  A) 110 N B) 4100 N C) 56 N D) 1000 N E) 450 N

[kilada]

Answer to Question 1

5.3 m/s

Answer to Question 2

D

[Ebrown]

Thank you!

[kilada]

Always glad to help...