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--- course_planning:computation:scratch_work [2016/03/12 22:44] – [Project 2: Part C: Escape from ice station McMurdo] obsniukm
+++ course_planning:computation:scratch_work [2016/03/25 18:40] (current) – [Code] obsniukm
@@ Line 22: / Line 22: @@
 Surprisingly enough hovercrafts are an expensive piece of kit. Your employer, the Carver Media Group, is concerned by the happenings at the McMurdo ice station and would like you to produce an accident report detailing the events after you lost control of your hovercraft.  The accident report should include a detailed computational model that provides the projected motion of the runaway hovercraft.
-<WRAP download 35%> Code for Project 2: Part C\\ Keep them in the same directory.\\ {{:183_projects:hovercraft.py|Project 2 Code (hovercraft.py)}}\\ {{:183_projects:physutil.py|PhysUtil Module}}</WRAP>
+<WRAP download 60%> Code for Project 2: Part C\\ Keep them in the same directory.\\ {{:183_projects:hovercraft.py|Project 2 Code (hovercraft.py)}}\\ {{:183_projects:physutil.py|PhysUtil Module}}</WRAP>
+====== Code ======
+<code python>
+#Objects
+hovercraft = sphere(pos=vector(-200,400,0), radius=1)
+#Parameters and Initial Conditions
+g = vector(0,-9.81,0)
+hovercraftm = 1500
+hovercraftv = vector(53.64,0,0)
+hovercraftp = runawaycraftm*runawaycraftv
+#Time and time step
+t=0
+tf=10
+dt = 0.01
+#MotionMap/Graph
+hovercraftMotionMap = MotionMap(hovercraft, tf, 5)
+#Calculation Loop
+while hovercraft.pos.x < 0:
+    Fgrav = hovercraftm*g
+    Fground = -Fgrav
+    Fnet = Fgrav + Fground
+    hovercraftp = hovercraftp + Fnet*dt
+    hovercraft.pos = hovercraft.pos + (hovercraftp/hovercraftm)*dt
+    hovercraftMotionMap.update(t, hovercraftp/hovercraftm)
+    t = t + dt
+</code>
+<WRAP tip>
+== Tutor Questions ==
+  * **Question:**  What assumptions did you make about the motion of the hovercrafts?
+  * **Expected Answer:**  That the runaway craft has a constant velocity, and the rescue craft starts from rest with a constant acceleration.
+  * **Question:**  Are these velocities and accelerations calculated from the numbers given exact?
+  * **Expected Answer:**  No, these are only average numbers, not instantaneous.  In order to get more "exact" numbers, we would need more data.
+  * **Question:**  Is the predicted position of the rescue craft a good one?
+  * **Expected Answer:**  Not really, basing the trajectory off the first 20 seconds of data is probably not the best -- but it is all we have to work with.
+  * **Questions:**  Can you draw a plot of position vs. time for both crafts?  What are the important features of this graph?
+  * **Expected Answer:**  The point where the two curves cross is when we should jump.  One should be linear, the other quadratic.
+  * **Questions:**  Can you draw a plot of velocity vs. time for both crafts?  What are the important features of this graph?
+  * **Expected Answer:**  The acceleration is the slope of each curve (constant in both cases).
+</WRAP>