Final answer:
The rate of heat flow through a wall can be calculated by determining the total thermal resistance and applying the formula Q = ΔT / R. The calculation changes when including elements like wooden studs, which alter the wall's overall R-value and heat current.
Step-by-step explanation:
The question pertains to the subject of physics, specifically to the topic of heat transfer through materials which is part of the thermodynamics branch. Using the given information, we can calculate the total thermal resistance (R-value) of the wall and then apply the formula for steady-state heat flow, which is Q = ΔT / R, where Q is the heat flow rate, ΔT is the difference in temperature across the wall, and R is the total thermal resistance.
(a) To calculate the rate of heat flow through the wall when it is made up of a layer of drywall with an R factor of 0.56, fiberglass batts, and insulated siding with an R factor of 2.6, we add these R-values together for the total resistance. The temperature difference (ΔT) is 22 °C (inside) - (-2 °C) (outside) = 24 °C. With this temperature difference and the total R-value, we can calculate Q. (b) When considering the addition of 2-by-4 studs in the wall, which have a different thermal resistance than the insulation, the overall R-value of the wall changes and thus alters the heat current.