What is Graphical Representation of Motion?
When objects move, we want to understand how they move — are they speeding up, slowing down, or moving at a steady pace? Numbers alone can be hard to interpret, but graphs give us a visual picture of motion that makes patterns immediately obvious.
In physics, we use two main types of motion graphs:
- Distance–time graphs (also called position–time graphs)
- Speed–time graphs (also called velocity–time graphs)
Each type tells us something different about the motion of an object. Learning to read and draw these graphs is one of the most important skills in mechanics.
A visual representation of an object's movement, showing how quantities like distance or speed change over time.
Think of a motion graph like a story told without words. Just by looking at the shape of the line, you can tell whether a character in the story is running, walking, or standing still — no numbers needed!
Distance–Time Graphs: The Basics
A distance–time graph plots the distance an object has travelled (on the vertical y-axis) against the time taken (on the horizontal x-axis).
A graph showing how far an object has travelled from its starting point over a period of time. Time is plotted on the x-axis and distance on the y-axis.
The shape of the line tells us about the type of motion:
- Horizontal (flat) line → The object is stationary (not moving). Distance is not changing.
- Straight diagonal line → The object is moving at constant (steady) speed. Equal distances are covered in equal time intervals.
- Curved line (getting steeper) → The object is accelerating (speeding up). Distance increases more and more each second.
- Curved line (getting shallower) → The object is decelerating (slowing down). Distance increases less and less each second.
On a distance–time graph, the object can never go "backwards" to a smaller distance value — distance is always zero or positive. However, if you are plotting displacement (which includes direction), the line can go downward.
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