Doug rubs a piece of fur on a hard rubber rod, giving the rod a negative charge. Which of the following statements best describes what happens in this process?A) Protons are removed from the rod. B) Electrons are added to the rod. C) The fur is also charged negatively. D) The fur is left neutral.

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up