Heat flows through a certain wall at a rate of h, when the temperatures on either side of the wall are tc and th the dimensions of the wall are a and b. you want to add a layer of insulation to the wall to reduce the rate of heat flow by percentage p. the insulating material is to have thermal conductivity k and thickness w. (a) draw two pictures: one of the original wall, and one with the layer of insulation added label all relevant information (b) derive an expression for w in terms of ht tc th a b p and . (c) calculate a value for wif k 0.0800 w/m-k a 3.00 m b 5.00 m tc 20.0 °c th-32.0 °c h1 1500 w p-90.0%