Uniform linear motion

turtles-own 
[d_x]

globals
[s v B d_t]

to setup
  clear-all
  setup-cestica
  setup-pozadina
  reset-ticks
end 

to setup-pozadina
   ask patches
   [
     set pcolor white
   ]
   set B random 15
   ask patch -10 0 
   [
     set pcolor grey
     set plabel "A"  
   ]
   ask patch B 0 
   [
     set pcolor grey
     set plabel "B"
   ]
end 

to setup-cestica
    create-turtles 1
    ask turtle 0 
    [
    set color red
    setxy -10 0
    set heading 90
    set shape "car" 
    if path? 
    [
      pen-down
    ]
    ]
end 

to go
  ask turtle 0 
  [
  ifelse xcor <= B
  [
  unos
  izracun
  ]
  
  [ 
  set v 0
  ]
  ]
  tick
end 

to unos
    set v speed
    set d_t 0.001
end 

to izracun 
  set d_x (v * d_t)
  set xcor (xcor + d_x) 
  set s (s + d_x)
end