(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A pressure cooker is a pot whose lid can be tightly sealed to prevent gas from entering or escaping.

1-If an otherwise empty pressure cooker is filled with air of room temperature and then placed on a hot stove, what would be the magnitude of the net force F_120 on the lid when the air inside the cooker had been heated to 120 degrees C Assume that the temperature of the air outside the pressure cooker is 20degrees C (room temperature) and that the area of the pressure cooker lid is A. Take atmospheric pressure to be p_a.

Treat the air, both inside and outside the pressure cooker, as an ideal gas obeying pV=N*k_B*T.

Express the force in terms of given variables.

2- The pressure relief valve on the lid is now opened, allowing hot air to escape until the pressure inside the cooker becomes equal to the outside pressure p_a. The pot is then sealed again and removed from the stove. Assume that when the cooker is removed from the stove, the air inside it is still at 120 degrees C.

What is the magnitude of the net force F_20 on the lid when the air inside the cooker has cooled back down to 20 degrees C?

Express the magnitude of the net force in terms of given variables.

2. Relevant equations

delta_U = n*C_v*delta_T

pV = N*k_B*T

F=pA

3. The attempt at a solution

I am realy stuck with this one, at first I tried re-arranging the equation given in terms of V to equate final and initial but that didn't work, can someone please give me a push in the right direction.

Cheers.

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# Pressure Cooker

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