Question

Distance covered by a particle never becomes zero between any interval of time but displacement becomes zero.

Answer 1

of course, you' re right ! distance covered by particle never becomes zero between any interval of time when particle is moving. Because distance is length of path covered by particle. While displacement becomes zero because displacement is the shortest distance between two position of particle. It doesn't depend upon path of particle . That's why when any particle moves in circular path displacement goes to zero on every rounds but the distance doesn't become zero . It is equal to product of number of round and circumference of circular path.

One more relation is important to note that distance is always greater than equal to displacement. I mean, distance ≥ |displacement|
only one case , in which distance becomes equal to magnitude displacement. e.g., one dimensional motion or linear motion.