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--- course_planning:183_projects:s23_week_3_geostationary_orbit [2023/01/25 19:09] – hallstein
+++ course_planning:183_projects:s23_week_3_geostationary_orbit [2023/01/25 19:34] – hallstein
@@ Line 282: / Line 282: @@
     Earth.rotate(angle=theta, axis=vector(0,0,1), origin=Earth.pos)
 </code>
+Changes made to the given code:
 ====== Project 3: Part C: Geostationary orbit ======
@@ Line 293: / Line 295: @@
 Inside the while loop, add: graphExample.plot(t, mEarth)
+====== Project 3: Part D: Geostationary orbit ======
+On a single graph, plot both the x-component of the satellite's momentum and the x-component of the net force acting on the satellite.
+Solution code for parts C and D
+<code>
+GlowScript 2.9 VPython
+get_library('https://cdn.rawgit.com/PERLMSU/physutil/master/js/physutil.js')
+#Window setup
+scene.range=7e7
+scene.width = 1024
+scene.height = 760
+#Objects
+Earth = sphere(pos=vector(0,0,0), radius=6.4e6, color=color.blue)
+Satellite = sphere(pos=vector(42164e3, 0,0), radius=1e6, color=color.red, make_trail=True)   #modify position of satellite
+#Parameters and Initial Conditions
+mSatellite = 15e3   # edit mass of the satellite
+pSatellite = mSatellite*vector(0,3073,0) #edit momentum of the satellite
+G = 6.67e-11   # add universal gravitational constant
+mEarth = 5.97e24  # add mass of Earth
+#Time and time step
+t = 0
+tf = 60*60*24
+dt = 1
+#MotionMap/Graph
+SatelliteMotionMap = MotionMap(Satellite, tf, 20, markerScale=2000, labelMarkerOrder=False)
+FnetMotionMap = MotionMap(Satellite, tf, 20, markerScale=2000, labelMarkerOrder=False)   # add Fnet force arrows - also need to add in loop)
+#separationGraph = PhysGraph(numPlots=1)
+graphSatellite = PhysGraph(numPlot=1)
+graphFnet = PhysGraph(numPlots=1)
+graphpF = PhysGraph(numPlots=2)
+#Calculation Loop
+while t < tf:
+    rate(10000)
+    Fgrav = -G*mSatellite*mEarth*Satellite.pos/(mag(Satellite.pos)**3) # Add Fgrav change Fnet
+    Fnet = Fgrav                                                       # change Fnet from zero
+    pSatellite = pSatellite + Fnet*dt
+    Satellite.pos = Satellite.pos + (pSatellite/mSatellite)*dt
+    SatelliteMotionMap.update(t, pSatellite/mSatellite)
+    FnetMotionMap.update(t, Fnet)  # Add Fnet vector arrows
+    #separationGraph.plot(t,mag(mSatellite))
+    graphSatellite.plot(t,mag(Satellite.pos))
+    graphFnet.plot(t,mag(Fnet))
+    scale=1.0E4   # add scale to make fluctuations in Fx visible (units of 10^-4 N)
+    graphpF.plot(t,pSatellite.x,scale*Fnet.x)
+    t = t + dt
+    #Earth Rotation (IGNORE)
+    theta = 7.29e-5*dt
+    Earth.rotate(angle=theta, axis=vector(0,0,1), origin=Earth.pos)
+</code>
+Modification of solution to part B to get |r| vs t, |Fnet| vs t and Fnet,x and P,x vs t: