Aheat-conducting rod, 0.90 m long and wrapped in insulation, is made of an aluminum section that is 0.20 m long and a copper section that is long. both sections have a cross-sectional area of the aluminum end and the copper end are maintained at temperatures of and respectively. the thermal conductivities of aluminum and copper are 205 w/m ∙ k (aluminum) and 385 w/m ∙ k (copper). what is the temperature of the aluminum-copper junction in the rod with steady state heat flow?

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?