1. oil or water clinging to a surface of a jar is an example of: a) lubrication b) adhesion c) force d) magnetism 2. friction always results in the loss of energy, force, electrons, or heat in the form of energy, force, heat, or electrons. 3. what do tire treads, rubber mats, automobile brakes, and tennis shoes have in common? a) they reduce friction b) they are lubricants c) they increase friction d) they reduce static electricity

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?

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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