Please full and correct answers (I re-posted it so a real expert can answer), these questions have long solutions.

4. Polyurethane foam (k = 0.025 W/m K) is used to insulate cylindrical water heaters. The polyurethane foam is sandwiched between two thin metallic layers as shown in the figure. The thickness of the polyurethane layer is 4 cm, while the internal radius of the tank is R = 40 cm. Assume that the internal metallic layer is always at the temperature of the hot water (55 C) and that the outer layer loses heat by convection to the surroundings at T = 10 C, with h = 50 W/mK. The length of the tank is 2 m and heat losses from the end surfaces are negligible. If the cost of energy is $ 0.10/kWh, determine the cost of the energy losses from the tank per day. Assume steady state. What would be the cost if there were no insulation? Air Hot water Thin me ta llic layers R Polyurethane foam