A hand$-$driven tire pump has a piston with a $2\mathrm{.}4$ cm diameter and a maximum stroke of $28$ cm$.$

Part $($a$)$ How much work do you do in one stroke if the average gauge pressure is $2\mathrm{.}1105$ N$/$m$2?$

Part $($b$)$ What average force do you exert on the piston, neglecting friction and gravitational force?