A child wants to pump up a bicycle tire so that its pressure is 1.2 × 10⁵ Pa above that of atmospheric pressure. If the child uses a pump with a circular piston 0.035 m in diameter, what force must the child exert? A)120 N B)89 N C)76 N D)54 N E)240 N

Question

Quizplus · Accepted Answer

The force required to pump up the tire is equal to the pressure difference between the tire and the atmosphere multiplied by the area of the piston. The pressure difference is 1.2 × 10⁵ Pa, and the area of the piston is π(0.035 m/2)² = 9.62 × 10^-3 m². Therefore, the force required is (1.2 × 10⁵ Pa)(9.62 × 10^-3 m²) = 120 N.

A Child Wants to Pump Up a Bicycle Tire So