You drop 12 balls off of a platform that is an unknown distance above the ground and measure the time it takes for the ball to fall to the ground. how far above the ground is the platform? give a range for this answer that you can be 95% sure that the true distance lies within. assume that g = 9.80 m/s2. all times are given in seconds

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