We know that pressure is the force applied into a surface, in our case the wall of the room, so then first we will calculate the surface of this wall: S = 2.2 * 3.2 = 7.04 m2 Then we also know the atmospheric pressure in normal conditions is 1 atm. That is the same 1 atm = 101325 Pascals or 101325 N/m2 Now we need to use the formula : P = F/S where P is pressure, F is force and S is surface to calculate the force: F = P * S = 101325 * 7.04 = 713,328 Newtons Conclusion: the force acts on the wall due the air inside the room is 713,328 N