An Alien race have perfected a means of transportation allowing individuals to move at 89.9% the speed of light through the universe. Suppose one of
these individuals sets out on a journey to the Andromeda Galaxy, which is
approximately 2.00 E 6 lt*yr away when measured from the Earth. How far apart will
the Milky Way Galaxy and the Andromeda Galaxy be as measured by the astronaut in
the ship?

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