Distance-Time Graphs

Understanding Distance-Time Graphs

• A distance-time graph represents the movement of an object over a period of time.
• On these graphs, the horizontal axis (x-axis) measures time (t), and the vertical axis (y-axis) measures distance (d).
• The slope or gradient of a line on a distance-time graph represents the speed of the object.

Key Features of Distance-Time Graphs

• A horizontal line depicts an object at rest. The object’s distance from a point doesn’t change over time, meaning speed is zero.
• An upward sloping straight line shows that the object is moving at a steady speed. The steeper the slope, the faster the speed.
• A curve on a distance-time graph means the object is accelerating or decelerating. A curve that slopes upwards shows an increase in speed (acceleration), while one that slopes downwards shows a decrease in speed (deceleration).

Interpreting Distance-Time Graphs

• The steepness of the slope can be used to calculate the speed of the object. Speed (S) is calculated by dividing the change in distance (Δd) by the change in time (Δt).
• The area under the graph line represents the total distance travelled by an object. Remember this is only true for velocity-time graph not for Distance-Time Graph.

Plotting Distance-Time Graphs

• To plot a distance-time graph, start by recording the distance travelled in regular time intervals. Plot these data points on the graph.
• Lastly, draw a line or a curve through the points.

Analysing Real-Life Situations

• Distance-time graphs can help analyse real-life situations. For example, they can tell whether a car was stationary, moving at a constant speed or accelerating over a period of time.
• In some cases, an object’s direction could be determined from the graph. For example, if the distance from a reference point is decreasing, the object is moving towards the reference point.