Two forces Fa and Fb are applied to an object whose mass is 8.0 kg. The larger force is Fa. When both forces point due east, the object’s acceleration has a magnitude of 0.5 m/s2. However, when Fa points due east and Fb points due west, the acceleration is 0.4 m/s2, due east. Find (a) the magnitude of Fa and (b) the magnitude of Fb.

You need to be more specific.  i really don't know what a "motion map" is.you can draw a graph of an object's position, distance, displacement, speed,velocity, or acceleration versus time, or you can draw a graph of the object's x-position versus its y-position and not give any information about time at all.if the graph presents position or displacement against time,  then constant velocity is a straight line . . i.e. a line that has  constant slope.if the graph shows speed against time, then constant velocityis a horizontal piece of line.if the graph shows acceleration against time, then constant  velocity is a piece of line that lies on the x-axis . . it's value is zero.