question_answer

Air is contained in a piston - cylinder arrangement as shown in Fig. with a cross - sectional area of \[4\text{ }c{{m}^{2}}\]and an initial volume of 20 cc. The air is initially at a pressure of 1 atm and temperature of \[20{}^\circ C.\] The piston is connected to a spring whose spring constant is\[~k\text{ }=\text{ }{{10}^{4}}\] N/m, and the spring is initially undeformed. How much heat (in joule) must be added to the air to increase the pressure to 3 atm. (For air,\[{{C}_{V}}=\text{ }718\]\[J/kg{}^\circ C\] molecular mass of air 28.97)            

Answer:

12.74