Who says it's not accounted for? Given a specific setup, you could for example, have one piston compressing gas and another piston using that compression but with a different ratio. If on the other hand, you have a fixed container, nothing is moving so no work is being done on the container.HummusAkemi said:So the internal energy of a system changes if work or heat is transferred between itself and its environment. Say you compress a gas and therefore do work on it, increasing its internal energy. According to Newton's 3rd law, shouldn't the gas also do work on its surroundings. How come this isn't accounted for?
It is accounted for. The gas is doing negative work on the surroundings.HummusAkemi said:So the internal energy of a system changes if work or heat is transferred between itself and its environment. Say you compress a gas and therefore do work on it, increasing its internal energy. According to Newton's 3rd law, shouldn't the gas also do work on its surroundings. How come this isn't accounted for?
Newton's 3rd Law states that for every action, there is an equal and opposite reaction. This means that when one object exerts a force on another object, the second object will exert an equal and opposite force back on the first object.
In terms of work, Newton's 3rd Law means that if an object exerts a force on another object and causes it to move, the first object will experience an equal and opposite force in the opposite direction. In terms of heat transfer, this law applies to the movement of molecules. When molecules collide, they exert equal and opposite forces on each other, causing heat to transfer from one object to another.
Internal energy is the total energy stored in the microscopic particles of a substance. This includes the kinetic energy of the particles as they move and vibrate, as well as the potential energy of their interactions. The internal energy of a substance is affected by factors such as temperature, pressure, and the number of particles present.
When work is done on a system, it can increase the internal energy of the system. This can be seen in the form of an increase in temperature or a change in the state of matter. For example, when a gas is compressed, work is done on it and its internal energy increases, causing an increase in temperature.
Heat transfer is the movement of thermal energy from one object to another. This thermal energy is a form of internal energy, so heat transfer can cause a change in the internal energy of a substance. For example, when heat is added to a substance, the internal energy of the substance increases, causing a rise in temperature.