Final answer:
The relationship of work (W) to the system is governed by the first law of thermodynamics, which states that the change in internal energy of a system (ΔU) equals the heat added to the system (Q) minus the work done by the system (W). Positive work occurs when the system performs work on its surroundings, and negative work when work is done on the system. Friction causes losses that require additional input work for a given work output.
Step-by-step explanation:
The relationship of work (W) to the work done by the system involves the concepts of net heat transfer and the first law of thermodynamics. When a system performs work on its surroundings, this work is considered positive. Conversely, when work is done on the system, such as compressing a gas, the work is negative. According to the first law of thermodynamics, the change in the internal energy of the system (ΔU) can be calculated via the formula ΔU = Q - W, where Q is the heat transferred into the system and W is the work done by the system.