1st Law of Thermodynamics

Physics homework example showing how to determine if the work done, change in internal energy, and heat are positive, negative, or zero for two different process, including isobaric (constant pressure) and isovolumetric or isochoric (constant volume). This tutorial is an excerpt from the "Topic 12-B - Laws of Thermodynamics" lesson in a complete course in Physics Homework Examples (including 27 topics and 230 tutorials in all topics of Physics) available on http://www.PhysicsVodcasts.com.

Category:

Education

Tags:

• thermodynamics
• work done by a gas
• work done on a gas
• positive work
• negative work
• heat absorbed
• heat given off
• change in internal energy
• Pressure-Volume graph
• PV graph
• isobaric
• isovolumetric
• isochoric
• physics vodcasts
• physics tutorials
• physics examples
• physics homework
• AP Physics
• physics help
• physics podcasts
• physics video
• Sioux Falls Physics

[evanmalmud]

What if the Work is bigger than the heat absorbed than the answer would be positive....

I don't know why you don't just do out the entire problem. No physics exam or hw is going to only ask for a sign.

[SiouxFallsPhysics]

@evanmalmud I assume you're talking about the 1st (isobaric) example . . . delta U is determined independently from the change in temp, so for this particular process type, it would be impossible for the positive Work to be greater than the negative Heat. It's actually relatively common to have a few problems in this topic that ask for signs only, but if you want more examples with numbers, the Fluids & Thermal series has 30 examples and is $4 on our web site

[xerokhan1]

this vedio style is very good but it is not more easy mathod for the !st law of thermodynamics