The brakes of a truck of mass 3500 kg break loose. The truck moves from rest down a 15° incline 46.4 m long and collides with a stationary car of mass 920 kg at the bottom. The truck and car lock and skid 48 m together before coming to a stop. What is the coefficient of kinetic friction between the tires and the road?

Wish i knew this to !

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.