Two point charges q, +4.60 nc and 02--2.90 nc are separated by 45.0 cm. (a) what is the electric potential at a point midway between the charges? (b) what is the potential energy of the pair of charges? what is the significance of the algebraic sign of your answer? o positive work must be done to separate the charges. o negative work must be done to separate the charges.

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