What does a constant slope represent on a distance-time graph?

A constant slope on a distance-time graph represents constant speed.

In a distance-time graph, the slope (or gradient) of the line indicates the speed at which an object is moving. When the slope is constant, it means that the object is travelling at a steady speed without any acceleration or deceleration. This is because the distance covered per unit of time remains the same throughout the journey.

To understand this better, let's break it down. The distance-time graph plots distance on the vertical axis (y-axis) and time on the horizontal axis (x-axis). The slope of the line is calculated by dividing the change in distance (Δy) by the change in time (Δx). If this ratio remains constant, the slope is constant, indicating that the speed is uniform.

For example, if a car travels 10 kilometres every hour, the graph will show a straight line with a constant slope. This straight line tells us that the car is moving at a constant speed of 10 kilometres per hour. If the line were to curve or change its slope, it would indicate a change in speed, either speeding up or slowing down.

In summary, a constant slope on a distance-time graph is a clear indicator of constant speed, making it easy to analyse and understand the motion of an object over time.