What do we need to measure in order to determine a star's luminosity?

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

What is the rate of 12 liters of water moving through a water hose in 4.0 minutes?

Use the profile illustrated for problem (1). assume that the layer of silty sand fill (sm) is placed over the entire site. estimate the thickness of the fill (h - in feet) that will cause the effective vertical stress at the center of the clay layer to increase by 517.5 pounds per square foot.