Question

If a line on a distance-time graph becomes steeper, what has happened to the speed of the object? What if it becomes a flat horizontal line?​

Answer 1

The speed of the object becomes higher as much steeper the line (on a distance-time graph) becomes.

If the line (on a distance-time graph) becomes a flat horizontal line, it means that the object's speed is cero, in other way the object stops.

A distance-time graph is a graph that plots the distance traveled by an object on a vertical axis against the time taken. The slope at any point represents the object´s speed at that specific moment. When the distance-time graph is a straight line, the object moves at a constant speed.