The ratio of displacement to distance for a moving particle is

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

Define and explain displacement.

What is a particle? How can we consider an object as a particle?

What is path length? What is displacement?

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.