Because ions in an ionic crystal are tightly bound together, it takes little energy to change them from a solid to a liquid state the charged particles are not free to move and conduct an electric current the ions of like charge strongly repel one another electricity easily flows between them

Ions are particles formed when an atom of an element looses or gains electrons to attain a stable configuration.They are either positively charged (cations) or negatively charged (anions). Ionic crystals consists of ions bound together by electrostatic attraction forming a regular arrangement, geometric structure called crystal lattice. In an ionic solid the ions are held by strong attractive forces (tightly bound) and cannot move from their positions in the crystal structure and  therefore, do not conduct electricity.

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction