An airplane flies $400 \,m$ north and $300 \,m$ south and flies $1200 \,m$ upwards,then the net displacement is (in $\,m$)

Does the displacement of an object depend on the choice of the origin of the coordinate system?

In which of the following examples of motion can the body be considered approximately a point object:
$(a)$ $A$ railway carriage moving without jerks between two stations.
$(b)$ $A$ monkey sitting on top of a man cycling smoothly on a circular track.
$(c)$ $A$ spinning cricket ball that turns sharply on hitting the ground.
$(d)$ $A$ tumbling beaker that has slipped off the edge of a table.

Which among path length and displacement cannot be zero for a moving object?

What is the relationship between the displacement and the path length of a moving object?

How can the resultant effect of motion be known?