Differences

This shows you the differences between two versions of the page.

--- summer_2019:gravitation [2019/07/30 13:31]
tallpaul
+++ summer_2019:gravitation [2019/08/06 02:56] (current)
tallpaul
@@ Line 1: / Line 1: @@
-===== Satellite Orbit Activity =====
 **Follow this link for the activity and the instructions: [[https://trinket.io/library/trinkets/4b1a7a7441|link]]**
+**Or, read the instructions after the image below, and copy the code into your own GlowScript file.**
 You should see something that looks like this:
-{{ satellite_trinket_screenshot.png | trinket screenshot}}
+{{ satellite_trinket_screenshot.png?800 | trinket screenshot}}
-If you click on the "Instructions" tab in the upper right, a set of instructions for the activity should pop up. Click between Instructions and Results to alternately view the instructions and the animation. If you prefer, the same instructions are also listed below.
+If you click on the "Instructions" tab in the upper right, a set of instructions for the activity should pop up. Click between "Instructions" and "Result" to alternately view the instructions and the animation. If you prefer, the same instructions are also listed below.
 . Run the code and see what happens! You should see a satellite shooting off into space, completely unaffected by gravity.
@@ Line 20: / Line 20: @@
 For more information on glowscript tools, check out: [[https://www.glowscript.org/docs/GlowScriptDocs/index.html]]
+<code>
+GlowScript 2.7 VPython
+# Window setup
+scene.width = 600
+scene.height = 400
+# Objects
+Earth = sphere(pos=vec(0, 0, 0), radius=6.4e6, texture=textures.earth)
+Satellite = sphere(pos=vec(7 * Earth.radius, 0, 0), radius=1e6, color=color.red, make_trail=True)
+# Parameters and Initial Conditions
+G = 6.7e-11
+mEarth = 6e24
+mSatellite = 20
+pSatellite = vector(0, 50000, 0)
+# Time and time step
+t = 0
+tFinal = 1 * 60 * 60 * 24     # 1 day
+dt = 1
+############################# Extra ##############################
+## energyGraph = graph(xtitle='time (s)', ytitle='energy (J)')  ##
+## kineticGraph = gcurve(color=color.green, label='kinetic')    ##
+## potentialGraph = gcurve(color=color.blue, label='potential') ##
+##################################################################
+################################# Extra Extra ###################################
+## FnetArrow = arrow(pos=Satellite.pos, axis=vec(0, 0, 0), color=color.yellow) ##
+#################################################################################
+# Calculation Loop
+while t < tFinal:
+    rate(10000)
+    Fnet = vec(0, 0, 0)
+    pSatellite = pSatellite + Fnet * dt
+    Satellite.pos = Satellite.pos + (pSatellite / mSatellite) * dt
+    t = t + dt
+    ############ Extra ############
+    ## kineticGraph.plot(t, 0)   ##
+    ## potentialGraph.plot(t, 0) ##
+    ###############################
+    ########### Extra Extra ###########
+    ## FnetArrow.pos = vec(0, 0, 0)  ##
+    ## FnetArrow.axis = vec(0, 0, 0) ##
+    ###################################
+    # Earth Rotation (just for fun!)
+    theta = 2 * pi * dt / tFinal
+    Earth.rotate(angle=theta, axis=vec(0, 1, 0), origin=Earth.pos)
+</code>