Awell-insulated house should have insulation with an r-value of at least r-19 in the walls
and an r-value of r-30 to r-44 in the ceilings. why is a higher r-value needed in the ceilings?

The magnitude of the poynting vector of a planar electromagnetic wave has an average value of 0.939 w/m^2 . the wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. how much total electromagnetic energy falls on the area during 1.0 minute?

Patricia is trying to compare the average rainfall of new york to that of arizona. a comparison between these two states for the months of july through september would best be measured in

Using the free-body diagram, calculate the net force acting on the sled. is the sled in a state of dynamic equilibrium?