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 Homework Statement:
 A firework goes off high above you, a distance d1=500m from your head, and you hear an acoustic pressure of 10Pa. Your sister is a distance d2=4.00x10^3 at the same time. If air absorbs 7.00 db/km in sound energy what sound level does your sister hear? Density of air=1.2kg/m^3....Speed of sound=343m/s.
 Relevant Equations:

I=pmax^2/2*density*velocity
I=power/Area
10log(I/I0)
This is the work I've done so far......
I=p^2/2dv........I=(10)^2/2(1.2)(343)=.12112
I(A)=P.........(.12112)(4pi(500)^2)=380522.366
I=P/A........380522.366/4pi(4000)^2=.0018925
10log(I/I0).......10log(.0018925/10^12)=92.77db
92.777(4)=64.77db
I am winging it and that's the closest I can get to the right answer which is 68.3db....
Any Guidance would be greatly appreciated!!!!
I=p^2/2dv........I=(10)^2/2(1.2)(343)=.12112
I(A)=P.........(.12112)(4pi(500)^2)=380522.366
I=P/A........380522.366/4pi(4000)^2=.0018925
10log(I/I0).......10log(.0018925/10^12)=92.77db
92.777(4)=64.77db
I am winging it and that's the closest I can get to the right answer which is 68.3db....
Any Guidance would be greatly appreciated!!!!