Question

when is a body said to be at rest

Answer 1

The body is said to be in rest when there is no change in its position with respect to time :)

Answer 2

Answer:

t=0

Usually, we consider time t=0, to denote the starting time of our observation. Your definition v=displacementtime makes sense if the body was initially (t=0) at rest at a position x=0 and you try to measure its velocity at a later time t.Apr 24, 2019