Question

under what condition can a body travel a certain distance and yet its resultant displacement be zero

Answer 1

if an object moves in circle is displacement is zero because when the body start moving it's initial point of object coming again that place so displacement is zero

Answer 2

If the body returns to its original position after covering some distance..
Then it is said to cover a distance but it's displacement is zero
Because displacement is the shortest distance between initial and final position of the object..
Which in this case will be zero..
Because the initial and final positions of the object are same.
Hope it helps..