If the x-axis represent time and the y-axis represents distance,
then the SPEED in meters/second is the SLOPE of the line
on the graph.
The object is moving, so the line is either rising or falling, but
it's definitely not staying horizontal, because the distance is
changing.
The object stops moving at 2.5 seconds, and stays stopped
for 0.5 second. So right at the 2.5 sec point, the line stops
sloping, and becomes horizontal until 3.0 sec.
We don't know what happens then. If the object stays still
for longer, then the line stays horizontal until the object starts
moving again. Then the line starts sloping again.
