What are the two forces that keep a pendulum swinging?

the length of the string and the mass of the bob

length and tension of the string

tension and gravity

length of the string and gravity

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

By what factor does the drag force on a car increase as it goes from 65 to 110 km/h?

Which of these has some mechanical energy? a. an atom b. heat inside earth c. a book on a shelf d. the fire from a lit match