Neutral atoms always have the same number of (3 points) a electrons and protons
b neutrons and electron
c protons and neutrons

The graph describes the motion of an object. the object moves with from a to b. it from b to c. it moves with from c to d.

This is the number of complete movements of a wave per second.

According to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does maria's voyage take according to samir?