The position-time graph of an object is found to be a straight line passing through the origin. what information about the motion of the object is provided by the graph?

Straight line . . . . .
-- Slope of the line is constant, so the object's speed is constant.

Passing through the origin . . . . .
-- When time was zero, position was zero.
-- So the object was moving before the starter fired his pistol, but it crossed
the starting line, at its constant speed, just as the shot sounded.

The graph shows that the object is travelling at uniform velocity, which initially started from zero.

The speed was not exceeded so it was slow