I am trying to clarify whether the two plates are separated by a distance. If they are, then the plates are not in contact, and the question becomes whether there is a force which can be used to push them together. If they are not separated by a distance, then they must be touching each other, and the question becomes whether there is a force which can pull them apart (as opposed to pushing them together).

I think this is an important distinction because it affects how we think about the question. In particular, if there is no possible way for the two plates to become separated or for them to touch each other without some external force acting on them, then we can assume that such forces exist and use them in our solution.

Last modified: October 8, 2022