Gohanchi

the formula for Q1 is Pgage = Pabs - Patm

Hey Im having a bit of trouble with this homework. Can someone please help me with this. A vehicle makes a long journey. Before leaving, the driver checks the pressure of all the tyres using a tyre pressure gauge. The inner volume of each tyre is 30 litres and the indicator on the tyre pressure gauge reads 235kPa (about 34.1 psi). This is the safe operating pressure for these types of tyres. At the time of departure, the local weather forecast indicates the ambient temperature is at 25°C and the atmospheric pressure is 101.325kPa. At the end of the journey, the driver stops to inspect the tyres and finds the average temperature of the tyres is now at 50°C. a) Calculate the absolute pressure of air inside the tyre at the start of the journey (units kPa)? b) What is the mass of air in each tyre at the start of the journey (units kg)? c) What is the expected new (absolute) pressure in each tyre at the end of the journey (units kPa)? d) If the driver needs to bring back the gauge pressure to its original value, what mass (units grams) of air must be released from each tyre (at 50°C) in order to bring each tyre back to its safe operating pressure.