Understanding Velocity-Time Graphs

Overview

A velocity-time graph displays how velocity changes over a specific period of time.
Velocity is shown on the y-axis and time on the x-axis. Both velocity and time must have appropriate units.
The graph can either be a curved line or a straight line, depending on the nature of movement.

A horizontal line indicates a constant velocity, meaning that the object is moving at a uniform speed without accelerating or decelerating.
A rising straight line indicates a positive acceleration - the object is speeding up.
A falling straight line indicates a negative acceleration or deceleration - the object is slowing down.
A curve sloping upwards suggests that acceleration isn’t constant, but increasing over time, as the object keeps speeding up faster and faster.
A curve sloping downwards means the deceleration is increasing; the object is slowing down at a greater rate as time passes.

The gradient of the line on a velocity-time graph indicates the acceleration or deceleration of the object. A positive gradient demonstrates acceleration, whereas a negative gradient indicates deceleration.
The area under the graph between time t1 and t2 represents the displacement of the object during that period of time.

Start with marking the units correctly on both axes. Time is usually in seconds (s), and velocity can be in various units such as metres per second (m/s).
Plot the points given in the problem (or calculated) on your graph.
Draw the line of best fit: This could be a straight line or a curve, depending on the data.
Try practising with different problems and scenarios to become proficient in interpreting and drawing velocity-time graphs.

Velocity-Time Graphs are an important tool in physics to understand the motion of objects.
They provide detailed visual information about an object’s velocity and how it changes over a period of time.
These graphs are an excellent way to visually interpret data, making them an integral part of the study and practical application of algebra.