What can you say about the motion of a body if its velocity time graph is a straight line to the parallel?

When the slope of a speed-time graph is a straight line parallel to the time axis, the object is moving with uniform speed. Since there is no change in the velocity of the object (Y-Axis value) at any point of time (X-axis value), the object is said to be in uniform motion.

Speed time graph

Speed-time graphs are very useful when explaining the movement of an object. We can use them to discover whether or not the object is moving at any point in time. We can also use them to see what speed the object is travelling at that point in time. Employing data from the graph, we can calculate any acceleration, the change in speed and the change in time. We can also use graphs to calculate the distance travelled. The area under a speed-time graph represents the distance travelled.