Negative Work

[Jessie Hsu 1C]

Hi! I was doing the Sapling homework for Week 3/4 and question 17 involved a negative value for work. Can someone please explain why work done by the system is a negative value? Thanks!

[Mikayla Kwok 3K]

The problem states that work is done by a system, which means it is a negative value. I think we just have to remember that work done by a system is negative and work being done on a system is positive. The way I rationalize this is by saying that when the system is doing work, it is losing energy to do this work, which makes the value negative.

[Maya Johnson 2a]

When work is done to the system, the value is positive. When a system does work, the value is negative.

[Kiara Phillips 3L]

The best way to sum it us is to remember that when work is done to the system you get a positive value and when a system does work you get a negative value. I think this is the opposite for physics because there you are looking at what is happening to the universe verses chem where we are looking at the relationship in terms of the system.

[VincentLe_3A]

When a system does work, there is a negative value for work because you can think of it as energy being inputted (and thereby released) by the system. The surroundings of the system would then absorb that energy inputted. However, when work is done to a system, the system itself is essentially absorbing that energy, thereby making work positive.

[Shruti Kulkarni 2I]

When work is being done to a system, the work will be positive and if work is being done by the system, the work will be negative.

[Chudi Onyedika 3A]

If the system does the work, then the value is negative.

[Ven Chavez 2K]

Work done by the system is negative because the system is expending energy to complete a task which for our class will be expanding the volume of a container. Whereas, work being done on the system will most likely be in reference to the system or container being compressed which is a way of transferring energy from the surroundings into the system.

[Kiana Tashakori 1D]

The work done by a system is going to be negative because it is releasing/losing energy to its surroundings

[Neel Bonthala 2G]

Hey! So like others said, when a system does work on its surroundings, the work will be negative. This is why in our expansion example problems in class, they were all negative work. Expansion means the system is pushing the piston outwards, and thus doing work on its surroundings. Compression would be positive work, because the surroundings are doing work ON the system.

[Astha Sahoo 3I]

When work is done on the system, the system gives off energy to the surroundings instead of expending energy to do work, thus work is negative.

[705512695]

Work is negative when work is done on the system.

[Kiara Phillips 3L]

The reason why its negative is because we are not thinking about it in terms of physics where we think of work as leaving/entering the surroundings, we are concerned about the system.

[Zainab Jamali 1H]

If work is done on the system, w is a positive value. If the system does work, then w is a negative value. Hope that helps :)

[SamanthaTolentino 3D]

Work done by the system is a negative value because we are looking generally at the working being done TO the system. If the system does the work, it means that its losing it to its surroundings thus why the work of the surroundings would be positive and the system would be negative.

[Rose_Malki_3G]

This is because when a system is expanding/voluume is increase, it is doing work of expansion so its losing energy, explaining why the sign for work would be negative

[Jaden Joodi 3J]

Because the function for work is looking at work done from the perspective of the system. To the system, it is losing its ability to do work, by doing work.

[Emmeline Phu 1G]

Hi! When work is done by the system, the value is negative because it is losing/releasing energy into the surroundings through doing work. When work is done on the system, the value is positive because the system gains energy from its surroundings. Hope this helps! :)

[Keshav Patel 14B 2B]

If the work is negative than that means the system is doing work. When it does work it loses or uses energy hence the reason its negative.

[Justin Zhang_1A]

If work is negative then that means that the system is doing work on its surroundings, so it is losing energy.

[DPatel_2L]

If the system does work then the value is negative.

[Kathy_Li_1H]

Hi! If the system is doing work on the surroundings, then the work would be a negative value.

[Gabe_Ek 1G]

I believe that when work is done on the system, the work value is positive. But when the system does work then the value is negative.

[Rose_Malki_3G]

When the system is expanding/doing work, it is pushing eternal air out of the way in order to expand, therefore doing work. And when the system does work it is losing energy, making the work term a negative value

[Faith Lee 2L]

If a system is doing work, its internal energy should decrease (I like to think of myself as the system; if I exercise, I have less energy). Thus, work must be negative in order to lower the value of U.

[EnricoArambulo3H]

Work done by the system is a negative value because it will cause the internal energy of the system to decrease. Quantitatively speaking, U = q + w, and if the work being done by the system is less than zero, then it will cause a decrease in internal energy. I hope this helped!

[Edgar Velazquez 2K]

I believe that work done by the system is negative because it releases energy from the system. By the same idea, work done on the system is positive because energy is being put into the system. It can be confusing since, at least for me, there was never a good explanation given by the teacher/professor whenever I learned/relearned about work.

[James_Hankee_1C]

When work is negative the system performs the work. When work is positive the work is done to the system.

[Lesly Lopez 3A]

Hello, so when work is done by the system, the final value would be negative. This is because the system is losing energy into the surroundings by doing work. When work is done on the system, the resulting value would end up being positive because the system gains energy from its surroundings. For some reason, it took me a while to understand this but hope this kinda helps.

[Brittney Nguyen 2L]

As others have said, work being done by the system is negative. A helpful way to remember this is to visualize the system giving away work! Since its giving away work by doing work, work is negative for the system.

[Aria Movassaghi 1A]

when a system does work, the value for work will be negative.