Mathematics for IGCSE & O level - Graphs In Practical Situations (Section 7 - No. 9)
If the speed-time graph shows a horizontal line, what can you say about the object's acceleration?
The object is accelerating.
The object is decelerating.
The object has constant speed.
The object is at rest.
Explicación
A horizontal line indicates the speed is not changing, therefore acceleration is zero (constant speed).