energy of a system

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Dina 2k
Posts: 57
Joined: Wed Sep 18, 2019 12:17 am

energy of a system

Postby Dina 2k » Wed Jan 29, 2020 5:49 pm

can someone briefly explain the piston example the professor did in class today? how would the energy of the system decrease?

Zaynab Hashm 2I
Posts: 110
Joined: Wed Sep 11, 2019 12:15 am
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Re: energy of a system

Postby Zaynab Hashm 2I » Wed Jan 29, 2020 6:01 pm

Before releasing the compressed air, the system will have a high internal energy due to the high pressure inside. After releasing, there will be a work of expansion on the surroundings, and this in turn will decrease the internal energy of the system. In other words, the system loses energy.

Andrew Liang 1I
Posts: 105
Joined: Fri Aug 30, 2019 12:18 am

Re: energy of a system

Postby Andrew Liang 1I » Wed Jan 29, 2020 6:53 pm

The system loses energy by expansion because the internal energy is greater than the surroundings. To balance out the energy difference, the system will apply energy on the pistol and push it outwards, losing energy to the surroundings.

Esha Chawla 2E
Posts: 108
Joined: Thu Jul 25, 2019 12:17 am

Re: energy of a system

Postby Esha Chawla 2E » Wed Jan 29, 2020 7:00 pm

Dina 2k wrote:can someone briefly explain the piston example the professor did in class today? how would the energy of the system decrease?


Assuming that the piston can move, the system can increase its volume. In increasing volume, the system is doing work on the surroundings. In doing work on the surroundings, the system is losing energy.

005324438
Posts: 51
Joined: Sat Aug 24, 2019 12:16 am

Re: energy of a system

Postby 005324438 » Fri Jan 31, 2020 2:48 pm

When the piston moves out, something has to push it out. Assuming nothing from the outside is pulling it out, something on the inside must be using energy to push it out, so the system must be losing energy.


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