Energy Conservation Model

; This is a Conservation of Mechanical Energy model made by Dean Reese - dreese@tusd.net, Teacher at Tracy High School,
; Instructor for the SIMMS Project, and Instructor for LLNL's Computer Simulation Teacher Research Academy.  


globals [K U v g t]                                   ; defines the following variables: K - Kinetic Energy, U - Potential Energy, v - velocity, g - gravity, t - time

to setup                                              ; procedure for the setup button
  clear-all                                           ; restarts the world to the default setting
  reset-ticks                                         ; establishes a clock and sets clock to zero
  ask patches [set pcolor 98]                         ; sets background color
  create-turtles 1                                    ; creates the falling object
  [set shape "box"                                    ; sets shape to box
   set size 1.2                                       ; sets size of box to 1
   set color red                                      ; sets color of box to red
   set heading 180                                    ; sets direction of box to point down initially
   set xcor 5                                         ; sets x-position of box to 5
   set ycor height]                                   ; sets y-position of box to height chosen by the height slider
  
  set v 0                                             ; sets the initial value of velocity to 0
  set g 10                                            ; sets the value of gravity to 10
  set t 0                                             ; sets the initial value of time to 0
  set K .5 * mass * v * v                             ; sets initial Kinetic Energy value to be 1/2 m v^2
  set U mass * g * height                             ; sets initial Potential Energy to be m g h
end 

to go                                                 ; procedure for the go button
  every .0001 [set t t + .0001]                       ; allows time to tick up by increments of .0001 seconds for a smooth transition on graphs
  set v (g * t)                                       ; updates velocity every .0001 s via the equation vf = vo + a t
  set K .5 * mass * v * v                             ; updates Kinetic Energy every .0001 s via the equation 1/2 m v^2
  set U mass * g * ([ycor] of turtle 0)               ; updates Potential Energy very .0001 s via the equation m g h
  ask turtle 0 [set ycor ( height - (5 * t * t))]     ; updates the height of the box via the equation yf = yo + vo t + 1/2 a t^2
  if t >= sqrt ((2 * height) / g) [ stop]             ; stops the program when the box reaches the bottom of the frame via t = sqrt (2 height/g)
  tick                                                ; ticks ahead one iteration of the go procedure   
end