## negative Delta U

$\Delta U=q+w$

Posts: 49
Joined: Thu Jul 25, 2019 12:16 am

### negative Delta U

if you burn fuel what does it mean conceptually for the Delta U to be negative? can the system then not do work?

Connie Chen 1E
Posts: 51
Joined: Mon Jun 17, 2019 7:24 am

### Re: negative Delta U

Internal energy is the total store of energy in a system. When you burn fuel, that energy is released, so the final internal energy of the system will be less than the initial, resulting in a negative delta U.

Fatemah Yacoub 1F
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Joined: Thu Jul 11, 2019 12:16 am

### Re: negative Delta U

If you burn fuel you have a lot of heat lost, meaning the internal energy decrease, but since the energy is lost as heat it does not increase the capacity to do work.

805307623
Posts: 99
Joined: Fri Aug 09, 2019 12:17 am

### Re: negative Delta U

If the temp of the gas decreases, the gas molecules slow down, and the internal energy of the gas decreases. This means that ΔU is negative.

Leslie Almaraz 4G
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### Re: negative Delta U

are there any other cases where the change in internal energy will be negative?

Rebekah Alfred 1J
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### Re: negative Delta U

A negative delta U occurs when the final internal energy is lower than the initial internal energy.