When a block slips on a rough surface, the work done by the surface on block is negative, while the work done by block on surface is zero. While writing the first law of thermodynamics, I have considered the block as my system and surface as the surroundings.
By the first law of thermodynamics, $$\Delta U=Q-W$$
Where $W$ is zero.
Now here's the poblem: by the IUPAC convention of work done on the system being positive, we have$$\Delta U=Q+W$$ where $\Delta U$ and $Q$ are the same as the first equation, but $W$ is nonzero. Why aren't the two equations consistent?
