1. Do electric field lines start or end at a positive charge? What about a negative charge?
2. When there are two charges, the charges exert forces on one another. Under what conditions do the charges attract one another? Under what conditions do the charges repel? How does the force on a charge depend on the magnitude of the charge?
3. With two charges, if one charge has a larger magnitude than the other, which charge experiences more force?
4. There are many parallels between gravitation and electrostatics. What are the similarities between the two? What are the differences? What, for gravity, plays the role that E, the electric field, plays for electrostatics?