Practice question

**First law of thermodynamics** ΔU = Q - W, ΔU internal energy change (J), Q heat added to system (J), W work done by system (J), sign convention physics Q positive when added, W positive when done by system, energy conservation, for isochoric W=0 ΔU=Q, for adiabatic Q=0 ΔU=-W, for isothermal ΔU=0 Q=W, for cyclic ΔU=0 Q_net=W_net. Δ Q = μ C_p Δ T . μ = 0.7 , C_p = 29.1 , Δ T = 400 - 320 = 80 . Δ Q = 0.7 × 29.1 × 80 = 1632 J . Using first law ΔU = Q - W, W = ∫