Resultant force on aircraft door

[Andy21]

Homework Statement

The air pressure at the altitude an aircraft is flying at is 28kPa. If the pressure inside the cabin is maintained at 100kPa, what is the resultant force on a door of area 2m^2 in the side of the aircraft?

Homework Equations

The Attempt at a Solution

I am not sure whether the answer is 0N because the door must be stationary and therefore no resultant force must be acting on it or do you have to work out the pressures exerted on the door from outside and inside the aircraft and then subtract the smaller of the forces.

 

[kjohnson]

Yes, your looking for the resultant force from the pressure difference over that area. The reason the door doesn't move is because there is reaction forces applied by the hinges..so the true net force on the door is zero.

 

[Andy21]

thanks for the help