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--- course_planning:183_projects:f21_week_1_escape_from_ice_station_mcmurdo [2024/01/09 22:13] – hallstein
+++ course_planning:183_projects:f21_week_1_escape_from_ice_station_mcmurdo [2024/01/15 21:39] (current) – hallstein
@@ Line 101: / Line 101: @@
 </WRAP>
 <WRAP alert>
-**==Steps and Timning:==**
+**==Part A Steps and Timning:==**
   * 4 quadrants, including the table and representation 20 minutes
   * Runaway craft - constant velocity 30 minutes
@@ Line 116: / Line 116: @@
   * Graphing position and velocity of both crafts 75 min
-==Part B Timing==
+**== Teaching Points==**
-  * New 4 quadrants 15 min
+  * the rescue craft uses the average velocity over each interval
-  * Calculate the speed of the rescue craft at the edge, from $v_{jump}$ 30 min
+  * The average velocity used to find its acceleration is the instantaneous velocity at the midpoint in time.
-     * Kinematics $v_{edge}^2 = v_{jump}^2 + 2a\Delta x$ Could use from the beginning point, but the emphasis is on finding the velocity (horizontal) at the edge
+     * $a= \frac{v_f - v_i}{t_f - t_i}$
-     * Or, is time is short, assume $v_{edge}=v_{jump}$
+     * Ask what velocities do you use, and when do they occur?   At the midpoint in the interval
-     * Need to know horizontal v at the edge of the rescue craft to analyze its fall
+     * To help understand this, ask them t sketch a v-t diagram for constant acceleration - v increases at a constant rate.  Ask them where on their graph the constantly changing velocity(instantaneous) is equal to the average velocity over the interval.
-  *  Finding time to fall 45 min
+     * They can get the correct numerical value,but for the wrong reason (using times other than the midpoint) - ask them to explicitly show the velocities and times.
-     * Relaize fall time is independent of the (horizontal)velocity at the edge
+     *  Intro to kinematics - stress only valid for constant force motion.
-     * Could have a conversation about what impacts the x component of the velocity
-     * Kinematics: $\Delta y = \frac{1}{2} a t_{fall}^2$ to get fall time
-   * Finding landing point from the fall time for both crafts: $x=v_{edge}*t_{fall} 60 min
-   * Which craft is "safe"?
-   * Plot x and y vs time; and $v_x$ and $v_y$ vs time
-Parts A and B are meant to be done on the same day, but in practice half of the folks do not finish part B.  It's okay to spend the first part of McMurdo day 2 to complete part B.   Thye need to do this before doing the computational part C.
-/* **==Teaching and Discussion Points:==**
+Parts A and B are meant to be done on the same day, but in practice half of the folks do not finish part B.  It's okay to spend the first part of McMurdo day 2 to complete part B. They need to do this before doing the computational part C.
-  * Relative velocity: If you are here, moving with this velocity what do you observe?
-     * How is the river moving relative to the shore?
-     * How is the boat moving relative to the shore?
-     * If you were on a raft on the river, how would it move?
-  * They don't have a measuring tape, but they are told there are two docks on the same side of the river.
-     * How do we deal with the distance term?   Some may try to pace it off - not very precise
-     * This is where working in variables is critical.
-     * Realize the distance between the docks is constant, and they can equate two expressions for finding the distance to eliminate this variable.
-  * The problem requires some basic algebra that may be a blast from the past
-     * Encourage them to think back to algebra class and what they did with two equations and two unknowns.
-     * Solving a system of equations!
-*/
 </WRAP>
@@ Line 217: / Line 196: @@
   * If students are moving a bit more slowly, it is OK for them to only model the motion of the constant velocity hovercraft on Tuesday and to then consider the constant force hovercraft on Thursday for 15 minutes.
 </WRAP>
+<WRAP alert>
+**==Part B Steps & Timing==**
+  * New 4 quadrants 15 min
+  * Calculate the speed of the rescue craft at the edge, from $v_{jump}$ 30 min
+     * Kinematics $v_{edge}^2 = v_{jump}^2 + 2a\Delta x$ Could use from the beginning point, but the emphasis is on finding the velocity (horizontal) at the edge
+     * Or, is time is short, assume $v_{edge}=v_{jump}$
+     * Need to know horizontal v at the edge of the rescue craft to analyze its fall
+  *  Finding time to fall 45 min
+     * Relaize fall time is independent of the (horizontal)velocity at the edge
+     * Could have a conversation about what impacts the x component of the velocity
+     * Kinematics: $\Delta y = \frac{1}{2} a t_{fall}^2$ to get fall time
+   * Finding landing point from the fall time for both crafts: $x=v_{edge}*t_{fall} 60 min
+   * Which craft is "safe"?
+   * Plot x and y vs time; and $v_x$ and $v_y$ vs time
+==Teaching Points==
+  * The diagram can be tricky
+Parts A and B are meant to be done on the same day, but in practice half of the folks do not finish part B.  It's okay to spend the first part of McMurdo day 2 to complete part B. They need to do this before doing the computational part C.
+</WRAP>
 <WRAP info>
 ==Common Difficulties==
@@ Line 342: / Line 343: @@
   * It is worth your time if you have it, to ask students to represent the motion of the hovercraft with arrows to see how the velocity and momentum change in each direction. They can do this altering the [[https://github.com/perlatmsu/python-physutil/wiki/MotionMap-Class|MotionMap line of code]].
   * If students have time, they should model the second hovercraft and be able to explain differences in the motion.
+</WRAP>
+<WRAP alert>
+**==Part C  Steps & Timing==**
+  * Finishing Part B if needed: 30 min
+  * Recommend to start with constant velocity cart, then duplicate/ copy&paste for accelerating cart
+  * Comment code: 40 min
+  * Falling $\vec{F}_{net} = \vec{F}_{grav}: 55 min
+     * runawaycraft.p means momentum
+     * runawaycraft.pos means position
+  *  Copy for rescue craft: 65 min
+     * May spend some time on adding x-acceleration (x<0) or even beyond
+     * Is there a significant change in the x-velocity over the final 200m?  No, the fractional change will be quite small
+   * Adding velocity arrows - Motion Map: 70 min
+   * Questions: 85 min
+   * Extension: adding air resistance: 105 min
+      * This takes some time to complete, don't have them attempt if less than 10 minutes remaining
+      * Need to use velocity unit vector to give direction of $-\hat{v}$
+   * Second Extension Part D, launch at an angle
+      * part D is hidden ask to open up if needed
+      * should only do if completed air resistance first
+==Teaching Points and tips==
+  * Use Glowscript 2.9 Vpython
+      * Given in the starter code and will not work with the new version
+  * Comments are your friend!
+  * Inexperienced coder(s) should code
+      * With one code version being edited (additional computers can view via Zoom)
+      * If on Zoom, make sure everyone is engaged and not doing their own thing on their computer.
+  * Whiteboards and pseudocode
+      * Sometimes, they get stuck.   Have them write out what they want to do on the board(words and equations), then help with syntax.
+  * Final code should have four while loops
+      * 2 for each craft: for while y >0 (jump - as they are falling) & x<0 while they are still on top of the cliff
+      * Watch for using more complicated Python moves that inexperienced coders have never seen (for, if, etc.)
+  * May need to take some time to explain time updates
+      * t=t+dt
+      * May seem strange to novice coders, as algebraically it doesn't make sense
+  * If they get to the air resistance extension, the drag equation is in the notes
 </WRAP>