For an object moving on a straight line,draw $x-t$ graphs for:
$(i)$ When it is at rest.
$(ii)$ When it is moving with constant velocity in the positive direction.
$(iii)$ When it is moving with constant velocity in the negative direction.
$(iv)$ When it performs non-uniform motion.

(N/A) The motion of an object can be represented by a position-time $(x-t)$ graph.
$(i)$ When an object is at rest,its position $x$ does not change with time. The graph is a straight line parallel to the time axis.
$(ii)$ When an object moves with constant positive velocity,the position $x$ increases linearly with time. The graph is a straight line with a positive slope.
$(iii)$ When an object moves with constant negative velocity,the position $x$ decreases linearly with time. The graph is a straight line with a negative slope.
$(iv)$ When an object performs non-uniform motion,its velocity changes with time. The graph is a curve,indicating that the slope (velocity) is not constant.