## Negative work

$\Delta U=q+w$

Rita Chen 1B
Posts: 112
Joined: Sat Jul 20, 2019 12:15 am

### Negative work

When is work negative?

Daniel Toscano 1L
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Joined: Tue Nov 13, 2018 12:18 am

### Re: Negative work

When a system does work

Jessica Li 4F
Posts: 115
Joined: Fri Aug 09, 2019 12:16 am

### Re: Negative work

Work is negative when a system does work, which means that it expands. If you do work, you lose energy, so it is negative. On the other hand, work is being done on the system when it is compressed. Think of it as the system can expand by itself, but you have to do something to the system to compress it.

Matthew Tsai 2H
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

### Re: Negative work

When a system does work, it loses energy in the process, so the value for w is negative.

Jacob Motawakel
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### Re: Negative work

A system's work is negative when that system does work, Work is positive for a system if work is done on that system.

Callum Guo 1H
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### Re: Negative work

when your system does work. so in this class, most of the time its when a gas expands.

Amanda Mei 1B
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Joined: Sat Aug 24, 2019 12:16 am

### Re: Negative work

When a system pushes against an external force (pressure), it loses energy and thus work is negative. Usually this causes volume to expand.

HuyHa_2H
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Joined: Wed Sep 11, 2019 12:15 am

### Re: Negative work

Work is negative when a system is doing work because that's what it loses hence the negative. Conversely, it's positive if something else is doing work on the system.

Kayli Choy 2F
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

### Re: Negative work

Work = -(pressure)(FinalVolume - InitialVolume). Therefore, if your final volume is greater than your initial volume (gas expands) then your change in volume will be positive, so this is why work will be negative. Additionally if your initial volume is greater than your final volume (gas is compressed), then your change in volume will be negative, so work will be positive.

Matthew Chan 1B
Posts: 111
Joined: Sat Sep 07, 2019 12:16 am

### Re: Negative work

Work is negative when the system does work itself, which makes sense since the system is "losing" work/energy, which makes sense why it would be negative.

Nikki Razal 1L
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### Re: Negative work

when a system does work, it is by a negative sign

CalvinTNguyen2D
Posts: 102
Joined: Thu Jul 25, 2019 12:16 am

### Re: Negative work

Work, as viewed through the lenses of chemistry, is positive when it is being done ON the system. Therefore, work is negative when the system itself is doing work on the surroundings.

lauraxie2e
Posts: 108
Joined: Fri Aug 09, 2019 12:17 am

### Re: Negative work

when the system does work on the surroundings

Elizabeth Harty 1A
Posts: 125
Joined: Sat Jul 20, 2019 12:16 am

### Re: Negative work

When a system does work the value is negative

Ian Morris 3C
Posts: 101
Joined: Wed Sep 18, 2019 12:18 am

### Re: Negative work

if a system is negative, then it just has done work