Question

Look at the graphs (a) to (d) carefully and state, with reasons, which of these cannot possibly represent one-dimensional motion of a particle.

Answer 1

All the four graphs are impossible.
(a) A particle cannot have two different positions at the same time;
(b) A particle cannot have velocity in opposite directions at the same time;
(c) Speed is always non-negative;
(d) Total path length of a particle can never decrease with time
. (Note, the arrows on the graphs are meaningless).