Two long, silver rods (k = 400 W/mK, diameter = 10 mm) are soldered together end to end, with the solder having a melting point of 520°C. The rods are in air at 20°C with a convection coefficient of 10 W/m2K. Ignoring radiation, what is the minimum power input needed to complete the soldering? Comment on how including radiation would have affected your calculated estimate of power needed for the soldering.

2. Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. So it is no surprise that such clothing has largely replaced thick and heavy old- fashioned coats. Multilayered ski jacket REBUT

silicon carbide (T ≈ 300 K): k = 490 W/m⋅K