What is electricity ?​

You throw a small rock straight up from the edge of a highway bridge that crosses a river. the rock passes you on its way down, 7.00 s after it was thrown. what is the speed of the rock just before it reaches the water 28.0 m below the point where the rock left your hand? ignore air resistance.

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

Select the best definition for wavelength. the height of an oscillating electromagnetic wave the rate at which electromagnetic waves oscillate. the distance between two crests of an electromagnetic wave. the oscillations of electric and magnetic fields select the best definition for frequency. the oscillations of electric and magnetic fields. the height of an oscillating electromagnetic wave. the distance between two crests of an electromagnetic wave. the rate at which electromagnetic waves oscillate