How Do You Calculate Work Done by an Expanding Gas?

  • Thread starter Thread starter brilyn
  • Start date Start date
  • Tags Tags
    Heat Work
Click For Summary
SUMMARY

The work done by an expanding gas in a cylinder at a constant pressure of 6000 Pa can be calculated using the formula W = PΔV. Given a piston area of 0.1 m² and a displacement of 5 cm, the correct approach involves calculating the change in volume (ΔV) and then applying the pressure to find the work done. The initial calculation of force (F = 600 N) is accurate, but the work formula used (W = 1/2F(s²)) is incorrect for this scenario. Instead, the work done is directly derived from the pressure and volume change.

PREREQUISITES
  • Understanding of pressure calculations (P = F/A)
  • Knowledge of work done by gases (W = PΔV)
  • Familiarity with unit conversions (e.g., converting cm to m)
  • Basic principles of thermodynamics (heat transfer and internal energy)
NEXT STEPS
  • Learn about the ideal gas law and its applications in thermodynamics
  • Study the concept of work done in thermodynamic processes
  • Explore PV diagrams and how to interpret work as the area under the curve
  • Investigate the relationship between heat, internal energy, and work using the first law of thermodynamics (Q = ΔU + W)
USEFUL FOR

Students and professionals in physics, engineering, and thermodynamics who are looking to deepen their understanding of work done by gases and related calculations.

brilyn
Messages
2
Reaction score
0
A fas is in a cylinder is at pressure of 6000 Pa and a piston has an area of .1m^2. As heat is slowly added the piston is pushed up a distance of 5cm. Calculate the work done on the surroundings by the expanding gas. (Assume pressure stays constant).

Thus far i found the force using
P=f/a 6000Pa or 6000N/m^2=F/.1m^2 therefore F=600N Correct? i think I'm mixing up units, but then i used
W=1/2F(s^2) > 1/2(600N)(5cm)^2 > i get 7500N/cm^2 but these units don't seem right for work?
Can you help me with my units and this is the work done by the gas right?

To find the internal energy if 52J of heat is added do i just use Q=IE+W?
 
Physics news on Phys.org
brilyn said:
A fas is in a cylinder is at pressure of 6000 Pa and a piston has an area of .1m^2. As heat is slowly added the piston is pushed up a distance of 5cm. Calculate the work done on the surroundings by the expanding gas. (Assume pressure stays constant).

Thus far i found the force using
P=f/a 6000Pa or 6000N/m^2=F/.1m^2 therefore F=600N Correct? i think I'm mixing up units, but then i used
W=1/2F(s^2) > 1/2(600N)(5cm)^2 > i get 7500N/cm^2 but these units don't seem right for work?
Can you help me with my units and this is the work done by the gas right?

To find the internal energy if 52J of heat is added do i just use Q=IE+W?
W = P\Delta V

You are trying to use W = force x distance but Fds = PAdS = PdV. It is much easier to use PdV.

What is the change in volume? Multiply that by the pressure to get the work done. On a PV diagram, Work is the area under the graph.

AM
 

Similar threads

Confusion about work done by a gas - Thermodynamics
  • · Replies 15 ·
Replies
15
Views
2K
Work done on container receiving gas from high pressure container
  • · Replies 1 ·
Replies
1
Views
2K
Work done by gas expanding into a cylinder+piston system
  • · Replies 3 ·
Replies
3
Views
2K
Calculating work done by a gas
  • · Replies 2 ·
Replies
2
Views
900
Volume-pressure equation for an expanding ideal gas
  • · Replies 10 ·
Replies
10
Views
2K
Calculating Work Done by Gas at Constant Pressure
  • · Replies 2 ·
Replies
2
Views
3K
What Happens When Gas Expands at Constant Pressure?
  • · Replies 12 ·
Replies
12
Views
7K
Thermodynamic Cycle -- Work done as a function of Heat absorbed
  • · Replies 3 ·
Replies
3
Views
2K
Thermodynamics: Internal Energy, Heat and Work Problem
  • · Replies 1 ·
Replies
1
Views
2K
Work Done By Gases - Calculating Pressure, Volume & Heat
  • · Replies 4 ·
Replies
4
Views
2K