Trong một máy giao thoa Iâng, các khe được chiếu bởi ánh sáng đơn sắc có bước sóng   = 0,6 m. Khoảng cách giữa hai khi sáng =1mm . Khoảng cách từ mặt phẳng chứa
hai khi đến màn là D m =1 . Xác định vị trí của ba vân sáng đầu tiên (coi vân sáng chính
giữa là vân sáng thứ không)

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. 

Well in that case, since an object moves with a constant velocity, there will be no acceleration as it is not increasing in speed.