physics
posted by opp .
A sound wave with intensity 37 mW/m2 interferes constructively with a sound wave that has an intensity of 18 mW/m2. What is the intensity of the superposition of the two?

I =(I1)^2 +(I2)^2 +2sqrt(I1•I2)•cosφ
max: cosφ =1, then
I =I1^2 +I2^2 +2sqrt(I1•I2) =
= 37^2 + 18^2 +2•sqrt(37•18) =
= 1744.6 mW/m^2