What best describes why kepler’s observation of planetary motion is a law instead of a theory

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

The solar panels used by mark function because of the photoelectric effect. light shines on the cells causing electrons to be ejected from the metal, which produces an electric current. at night on mars, no light will fall on the solar cells and no electric current will be generated. according to your notes, what type of light is typically needed to cause the photoelectric effect? a)visible b)ultraviolet c)infrared

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?