In which condition acceleration of any object is zero? Give with example.​

Lets say that an object of a certain volume has a certin mass. what happens to its mass when you double its volume?

What will a positive and a negative charge do if they are separated from each other?

The field between two charged parallel plates is kept constant. if the two plates are brought closer together, the potential difference between the two plates either a) decrease b) does not change c) increase?