1. A sound is made by a speaker, which then radiates in all directions. The sound wave

is described by
A(r) sin(2r - 600t)
where the distances are in meters, and the time in seconds. The A(r) just indicates that
the amplitude has some distance dependence--it decreases smoothly as the wave gets
farther from the source

a) What is the velocity of this wave?

b) How long does it take for the sound to travel from the speaker to a listener 100 m
away (the length of a football field)?

1 answer

velocity?

freq*lambda=velocity

freq= 600/2PI

lambda= 2PI/2=PI

velocity= 600/2PI * PI= 300m/s