A typical pressure of the air near the earth’s surface is about 100 kP (= 10⁵ N/m²). It varies a little from place to place and day to day and with height. Some of this variation is responsible for the weather. (Hint: You may take the density of air to be about 1 kg/m³ for the purpose of estimation.)

a. Estimate the total upward force the pressure of air exerts on the ceiling of your dorm room.
b. Estimate the difference between the air pressure at the ceiling of the room and the floor.