Hi, I have a situation like the following and I need to calculate the force as well as the sound pressure exerts on a rectangular object. If I have a sound source which is mapped on a 10cm x 10cm square plane, and the sound source generates for example 20Pa (N/m2) . The generated sound travels and is reflected by another plane with the dimention 100cm x 100cm, and it comes back into its own square plane(10cm x 10cm). As far as I know, there will be a force exerted on the 10cm x 10cm plane by the reflected sound pressure. Assume the distance between 2 square planes is 1cm. Then how large that force would be. Thanks.