Question
A potato cannon has the fuel combusted, generating a lot of heat and pressure, which launch a potato. The combustion process _____ the internal energy, while launching the potato _____ the internal energy of the potato cannon.
- increases, increases
- increases, decreases
- decreases, increases
- decreases, decreases
Final Answer
(b)
Solution video
OpenStax College Physics for AP® Courses, Chapter 15, Problem 5 (Test Prep for AP® Courses)
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Video Transcript
This is College Physics Answers with Shaun Dychko. In a potato cannon, some fuel is combusted like maybe some hair spray is burned with piezoelectric lighter from a barbecue which I have done and it's fun and it generates a lot of heat and pressure, and it launches a potato and the combustion process increases the internal energy because it adds heat. As you know you've Delta U equals heat added to the system minus work done by the system and so the combustion is a positive Q so it increases internal energy or as launching the potato means the potato cannon is doing work on the potato and so that makes a positive W which reduces internal energy and so the answer is B.