Problem 4: Part A (15 points) Hot water flows through a glass tube of inner radius 3cm and outer radius 5 cm. The temperatures of the inner and outer surfaces of the tube are, respectively, 90C and 85C and the mean thermal conductivity of the glass is 0.84 W/mK. Calculate the rate heat loss (a) from the tube per unit length. Use equation q= (T; -- T2). Hint: It helps to convert cm to m. k2 Problem 4: Part B (20 points) Hint: Draw the radi carefully to assure you have the right radi to solve the Part B By how much is the rate of heat less decreased if the wall thickness of the tube is doubled? What is the delta (difference) between the heat loss of Part A to the heat loss of Part B? What observations can you make when the wall thickness if doubled