An object is thrown vertically upwards with an initial velocity of 20m/s from the edge of a cliff that is 30m from the sea below, as shown in figure 12.2 Determine:
A. Ball’s maximum height
B. Time taken for the ball to reach its maximum height
C. The Time to hit the sea
D. The speed with which it hits the sea
(You May approximate g by 10m/s)

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.