It has been proposed that extending a long conducting wire from a spacecraft (a "tether") could be used for a variety of applications, from navigation to power generation. one of the first such experiments involving this technique was an august 1992 space shuttle flight, but the tether failed and only only 250 m of the conducting wire could be let out. a 40.0 v motional emf was generated in the earth’s 5.0 × 10-5 t field, while the shuttle and tether were moving at 7.80 × 103 m/s.

Acarpenter builds an exterior house wall with a layer of wood 2.9 cm thick on the outside and a layer of styrofoam insulation 2.3 cm thick on the inside wall surface. the wood has k=0.080w/(m⋅k), and the styrofoam has k= 0.010 w/(m⋅k). the interior surface temperature is 19.0 ∘c , and the exterior surface temperature is -15.0 ∘c . a.)what is the temperature at the plane where the wood meets the styrofoam? celsius b.)what is the rate of heat flow per square meter through this wall? /m^2