Final answer:
To bring two negatively charged particles together, work must be done to overcome their repulsive electromagnetic force. In the case of separating two oppositely charged particles, work is also needed to overcome their attractive force.
Step-by-step explanation:
To bring two negatively charged particles together, you must overcome the electromagnetic force that causes them to repel each other. This repulsion is due to both particles having the same type of charge, and according to Coulomb's law, like charges repel each other. Overcoming this repulsive force requires external work or energy. On the other hand, to separate two oppositely charged particles, which attract each other due to their differing charges, you also need to perform work to overcome the attractive force acting between them. The closer the particles are, the stronger the attractive force and, consequently, the greater the energy required to pull them apart. Neutral objects can influence charge distribution upon contact, but to directly influence charged particles, as described, external energy is needed.