posted by Janus on .
An automobile tire contains a certain volume of air at 30 psig and 70 °F. The barometric pressure is 29.50 Hg. If due to running conditions, the temperature of air in the tire rises to 160 °F. What will be the gauge pressure?
Assume that air is an ideal gas & that the tire does not stretch.
At constant volume, the absolute pressure increaes in proportion to the absolute temperature increase.
P2/P1 = (344K)/(295K)= 1.166
29.50 ihches Hg = 14.45 psia atmospheric pressure
Original tire absolute pressure = 30.00 + 14.45 = 44.45 psia
Final tire absolute pressure = 44.45 * 1.166 = 51.83 psia
Final tire guage pressure = 51.83 - 14.45 = 38.4 psia
Make that psig for my last answer. (pounds per square inch, guage). The number is OK
Thank you very much