physics
A hand-driven tire pump has a 2.50 cm diameter piston and a maximum stroke of 31.0 cm.
(a) How much work do you do in one stroke if the average gauge pressure is 2.40 multiplied by 105 N/m2 (about 35 psi)? (You may consider this an isothermal process.)
(b) What average force do you exert on the piston, neglecting friction and gravity?
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Answers
a) Work done in one stroke = Area of piston * Pressure * Stroke
= (π/4) * (2.50 cm)2 * (2.40 × 105 N/m2) * (31.0 cm)
= 4.27 × 105 N·m
b) Average force on the piston = Work done/Stroke
= 4.27 × 105 N·m/31.0 cm
= 13720 N
We are neglecting friction and gravity in this calculation since the average force is calculated with respect to the work done in the system. Friction and gravity do not contribute to the work done, so they do not affect the average force on the piston.
