3) A bicycle tire pump has a piston with area 0.40 in². If a person exerts a force of 15 lb on the piston while inflating a tire, what pressure does this produce on the air in the pump?

4) A large truck tire is inflated to a gauge pressure of 62 psi. The total area of one sidewall of the tire is 1,170 in². What is the net outward force (in lb) on the sidewall because of the air pressure? (Enter the magnitude.) 

5) A viewing window on the side of a large tank at a public aquarium measures 47 in. by 52 in. The average gauge pressure from the water is 7 psi. What is the total outward force on the window?