Orbit

rem parameters are for a geostationary orbit arround earth
font "arial",10,100
height = 36000000
speed=3070
radius=6371000
time=0 : scale=400000 :dt=40 :g=9.81
x=0 : y=radius+height
px=0:py=0
xspeed=speed : yspeed=0
fastgraphics
loop:
dist=((x-px)^2 + (y-py)^2)^(1/2)
gravity= g*(radius/dist)^2
dx=x-px : dy=y-py
xac= (dx/dist)*gravity : yac= (dy/dist)*gravity
xspeed=xspeed-xac*dt : yspeed=yspeed-yac*dt
x=x+xspeed*dt : y=y+yspeed*dt
clg
Text 150 + x/scale,150 + y/scale,"[]o[]"
circle 150+px,150+py,radius/scale
time=time+dt
speed = int(((xspeed)^2 + (yspeed)^2)^(1/2))
text 10,10,"height = "+dist/radius+"radius"
text 10,30,"speed = "+speed+"m/s"
text 10,50,"time = "+int(time/3600)+"h"
text 10,70,"grav-acc = "+(radius/dist)^2+"g"
text 10,90,"centri-acc = "+(speed^2/dist)/g+"g"
refresh
goto loop