How do you solve the expandable gas cylinder problem with a spring?

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SUMMARY

The discussion centers on solving the expandable gas cylinder problem connected to a spring with a force constant of 2000 N/m. The initial conditions include a gas volume of 6.00 L at 1.00 atm and 20.0°C. The user attempts to calculate the height of the piston after increasing the temperature to 503 K but arrives at an incorrect height of 0.482 m. The correct approach involves using the ideal gas law (PV = nRT) and the relationship between pressure, force, and area to derive the correct equation for height.

PREREQUISITES
  • Understanding of the Ideal Gas Law (PV = nRT)
  • Knowledge of pressure calculations (P = F/A)
  • Familiarity with unit conversions (e.g., atm to Pa, L to m³)
  • Basic principles of thermodynamics related to gas behavior
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  • Review the derivation of the Ideal Gas Law and its applications
  • Learn about the relationship between pressure, volume, and temperature changes in gases
  • Study the mechanics of springs and their force constants in relation to gas systems
  • Explore advanced topics in thermodynamics, such as the First Law and its implications for gas behavior
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Touchme
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Homework Statement



An expandable cylinder has its top connected to a spring with force constant 2.00 103 N/m. (See Fig. P10.58.) The cylinder is filled with 6.00 L of gas with the spring relaxed at a pressure of 1.00 atm and a temperature of 20.0°C.


I searched for a similar question however I didnt understand it. Maybe it was the calculation error. Someone help me...

Homework Equations



PV = nRT
[PV/T]i = [PV/T]f
Volume of cylinder = Ah


The Attempt at a Solution



First I convert my units. Initial state: 101325 Pa, 293 K, and 0.006 m^3
I determined the constant by using the gas law PV/T. (101325)(0.006)/293 = 2.0749 [(Nm^2)/K].
After the temperature is increased to 503 K (273+230), the piston rises and the volume changes. The new volume is 0.006 + Ah = 0.006 + 0.01h. The pressure is equal to P = F/A. F is the force constant times dispalcement (h), which is 2000 N/m. P = 2000/0.01 = 200000h N/m^2.
Putting everything together we get
2.0749 = (200000h)(0.006+0.01h)/503

The answer h = 0.482 m or 48.2 cm is incorrect. Any suggestion or corrections. Thank you.
 

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Touchme said:

Homework Statement



An expandable cylinder has its top connected to a spring with force constant 2.00 103 N/m. (See Fig. P10.58.) The cylinder is filled with 6.00 L of gas with the spring relaxed at a pressure of 1.00 atm and a temperature of 20.0°C.I searched for a similar question however I didnt understand it. Maybe it was the calculation error. Someone help me...

Homework Equations



PV = nRT
[PV/T]i = [PV/T]f
Volume of cylinder = Ah

The Attempt at a Solution



First I convert my units. Initial state: 101325 Pa, 293 K, and 0.006 m^3
I determined the constant by using the gas law PV/T. (101325)(0.006)/293 = 2.0749 [(Nm^2)/K].
After the temperature is increased to 503 K (273+230), the piston rises and the volume changes. The new volume is 0.006 + Ah = 0.006 + 0.01h. The pressure is equal to P = F/A. F is the force constant times dispalcement (h), which is 2000 N/m. P = 2000/0.01 = 200000h N/m^2.
Putting everything together we get
2.0749 = (200000h)(0.006+0.01h)/503

The answer h = 0.482 m or 48.2 cm is incorrect. Any suggestion or corrections. Thank you.

You have to develop the equation for pressure:

[tex]P_f = P_i + kh/A = nRT_f/V_f[/tex]

Since [itex]P_i = nRT_i/V_i[/itex], and [itex]V_f = V_i + Ah[/itex]

you should be able to work that out for h.

AM
 

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