A hot-air balloon has a volume of 2800 m3m3 . The balloon fabric (the envelope) weighs 840 NN . The basket with gear and full propane tanks weighs 1500 NN . Part A If the balloon can barely lift an additional 2800 NN of passengers, breakfast, and champagne when the outside air density is 1.23 kg/m3kg/m3, what is the average density of the heated gases in the envelope

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.