Which of the following is most like the rotation of stars in the disk of the milky way?
the planets in our solar system
cars moving at a constant speed on a circular race track
a dvd in a player
the tire of a car moving

Cars moving at constant speed on a circular race track

Explanation:

Stars and gas in the galactic disk moves in a roughly circular path about the center of the galaxy

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.