State the sign convention for heat and work in thermodynamics.

(N/A) In thermodynamics,the sign conventions are defined based on the system's perspective:
$1$. Heat $(Q)$:
- If heat is added to the system,$Q$ is positive $(Q > 0)$.
- If heat is removed from the system,$Q$ is negative $(Q < 0)$.
$2$. Work $(W)$:
- If work is done by the system (expansion),$W$ is positive $(W > 0)$.
- If work is done on the system (compression),$W$ is negative $(W < 0)$.