A mechanical pump is used to pressurize a bicycle tire. The inflow to the pump is 0.6 cfm. The density of the air entering the pump is 0.075 lbm/ft3. The inflated volume of a bicycle tire is 0.040 ft3. The density of air in the inflated tire is 0.4 lbm/ft3. How many seconds does it take to pressurize the tire if there initially was no air in the tire?

Question

Emmett Knapp

Physics

6 December, 04:45

A mechanical pump is used to pressurize a bicycle tire. The inflow to the pump is 0.6 cfm. The density of the air entering the pump is 0.075 lbm/ft3. The inflated volume of a bicycle tire is 0.040 ft3. The density of air in the inflated tire is 0.4 lbm/ft3. How many seconds does it take to pressurize the tire if there initially was no air in the tire?

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Answers (1)

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Lawson Chapman · Answer 1

0.75 seconds

Explanation:

Given information

Inflow=0.6 cfm

Density of air entering = 0.075 lbm/ft3

Bicycle's inflated volume = 0.040 ft3

density of air in the inflated tire = 0.4 lbm/ft3

Mass of air pumped=density*volume=0.075*0.04=0.003 lbm

This mass of air pumped is same as mass of air in the inflated tire

Volume of inflated tire=mass/density=0.003/0.4=0.0075 ft3

Time=0.0075/0.6 = 0.0125 mins

0.0125*60=0.75 seconds