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## Homework Statement

Hi, I need a big help on how to carry on with this problem:

You witnessed the failure of a nylon rim which exploded injuring the person filling the tire with air. Develop a documented mathematical model that predicts the time required to reach a specific pressure. Your results are to be tabulated and plotted. Specifically predict the time to change from 100 kPa to 800 kPa. Assume the process is adiabatic and that the tire volume may be represented by a Torus (doughnut). In order work this problem you have to solve for pressure by iterating forwards in time.

Given:

Tire size 25 cm x 8 cm (outside diameter x width)

Rim diameter 11 cm

Air line pressure 1380 kPa

Initial tire pressure 100 kPa

Airline pipe area 32 mm2

Valve orifice area 6 mm2

Initial tire temp 16°C

## Homework Equations

Volume of torus = pi^2/4 D d^2

Area = pi^2 D d

## The Attempt at a Solution

I already got confused with what D is. Id D (25 + 11) = 36 inches or (25 - 11) = 14 inches? Then d is 16 inches because of 8 + 8 inches. HELP!

q = 0 since its adiabatic. But I can't find a formula that will harmonize pressure with time...

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