A certain source of sound waves radiates uniformly in all directions. At a distance of 20 m from the source the intensity level is 51 db.
What is the total acoustic power output of the source, in watts? (Note: The reference intensity I0 is 1.0 10-12 W/m2.)
Question 2
An airplane flies between two points on the ground that are 500 km apart. The destination is directly north of the origination of the flight.
The plane flies with an air speed of 120 m/s. If a constant wind blows at 10.0 m/s due west during the flight, what direction must the plane fly relative to north to arrive at the destination?
A) 4.78 west of north
B) 4.76 east of north
C) 4.78 east of north
D) 4.76 west of north
E) 85.2 west of north