How do velocity-time graphs depict changing motion?

Velocity-time graphs depict changing motion by showing how an object's velocity changes over a period of time.

In a velocity-time graph, the horizontal axis (x-axis) represents time, while the vertical axis (y-axis) represents velocity. The graph is a visual representation of an object's motion, with each point on the graph indicating the object's velocity at a specific point in time.

If the graph is a straight line, this indicates a constant velocity, meaning the object is moving at a steady speed in a single direction. The steeper the line, the greater the velocity. If the line is horizontal, it means the object is not changing its velocity, it is either at rest or moving at a constant speed.

A sloping line on a velocity-time graph indicates a changing velocity, which means the object is accelerating or decelerating. If the line slopes upwards, the object is accelerating. The steeper the slope, the greater the acceleration. Conversely, if the line slopes downwards, the object is decelerating or slowing down.

The area under the graph line represents the distance travelled by the object. This is because the area of a rectangle (which is what the area under the line essentially is) is calculated by multiplying the base (time) by the height (velocity). Therefore, the larger the area under the line, the greater the distance travelled by the object.

In summary, velocity-time graphs provide a visual way to analyse an object's motion, showing how its velocity changes over time, whether it's moving at a constant speed, accelerating, or decelerating, and the distance it has travelled.