Thermodynamics Crash Course Physics 23 Detailed Solutions and Problem Explanations

Apply the first law by writing ΔU = Q − W before inserting numbers. Problems in lesson twenty-three require tracking heat transfer, mechanical work, and internal energy change with consistent units, usually joules.

Each task here follows a fixed check order: identify the system, mark heat entering or leaving, then assign work sign based on compression or expansion. Missing sign conventions cause most calculation errors, especially in piston and gas container examples.

For state change questions, rely on initial and final values only. Path details matter for work but not for internal energy. Tables show correct substitutions and simplified results to confirm numerical accuracy.

Use these worked results to compare equations line by line. If a mismatch appears, review unit conversion, pressure–volume products, or algebra steps before rechecking the final value.