A bicycle tire pump has a piston with area 0.43 in . If a person exerts a force of 16 lb on the piston while inflating a tire, what pressure does this produce on the air in the pump? 

A large truck tire is inflated to a gauge pressure of 72 psi. The total area of one sidewall of the tire is 1,170 in . What is the net outward force (in lb) on the sidewall because of the air pressure? (Enter the magnitude.)