Atmospheric Pressure Problem?

Question

An airtight box has a removable (massless) lid of area 2·10-2 m2. A lid is placed on it while it is on top of a mountain (where Patm=0.87·105 Pa). It is then taken to sea level, where Patm = 1.013·105 Pa. How much force will be required to remove the lid?

Answer 1

Force = Pressure * Area

Multiply the pressure difference by the area given to get the force required to remove the lid.