Question

What frequency will you hear if a truck is driving toward you at 20 m/s sounding a horn of frequency 300 Hz. Assume the speed of sound to be 340 m/s.

Answer 1

=319Hz

Step-by-step explanation:

This question is on sound waves

General formulae;

Frequency of observer= f of source*[ (v of sound+ v of observer)/(v of sound-v of source)]

where f is frequency and v is velocity

Given;

Velocity of sound = 340m/s

frequency of source = 300 Hz

Velocity of observer=0m/s

Velocity of source/truck= 20m/s

Substitute values in the formulae;

Frequency of observer= 300× {(340+0)/(340-20)}

=300×{ 340/320}

=300×340/320

=318.75

=319Hz