if the mass of the skateboard doubled but the net force on it remained on a constant what would happen to the accelerationof the skate borad

Iwould sure like to answer your question but i honestly just don’t know

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. 

To a fellow spongebob-ian i will be glad to , the cheetah didn't get far on purpose because he's a cheetah  ( ͡° ͜ʖ ͡°)