Answer please, I really need some help

Steel water aluminum think about the three words listed here. which word could be added as the title of this list of words to tell how these words are related? a) conductors b) heat c) insulators d) metals

Herman is walking his pet fish, leo , back and forth along the canal. suppose the canal is 30 meters long and he goes up and back 25 times. a) what distance has herman walked?

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?