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--- 184_projects:f21_project_4 [2021/08/19 14:54] – dmcpadden
+++ 184_projects:f21_project_4 [2021/09/24 14:32] (current) – dmcpadden
@@ Line 2: / Line 2: @@
 ===== Project 4 =====
+==== Project 4A: StickyStuff and the Dust Particle ====
+{{  183_projects:taperoller.png?500}}
-==== Project 4A: Better Thundercloud Model ====
+Adhesive tape is manufactured by repeatedly rolling and unrolling large sheets of plastic, which can cause there to be a charge on the surface of the tape. Why this important you may ask? Trapped in the town of Lakeview, S.P.A.R.T.A.N force has been called to the premises of StickyStuff Corporation. StickyStuff Corp has been tasked with producing a special type of adhesive tape to be used on a new top-secret spacecraft called Artemis 13. Unfortunately, there has recently been a dust problem in the manufacturing plant. Dust particles (on average, $charge=0.802*10^{-14} C$, $m=5.5*10^{-8} g$) have been accumulating on the tape as it rolls through the assembly line. The problem has been isolated to a single roller, which operates for 10 seconds at a time at a power of 100 watts (where 1 watt = 1 J/s). Using your handy-dandy-super-extender tape measure, you find that exactly 30 m of tape passes over the roller during each 10 second time period. Your team needs to determine where to put a fan and how much force the fan needs to exert on each dust particle, such that the fan blows away any dust that may be attracted to the tape. The tape must be in excellent condition before being used on the spacecraft. From your adhesive engineering education, you have access to a [[https://www.alphalabinc.com/triboelectric-series/|table]] that you think may help.
+(There's actually a pretty cool "How it's Made" video [[https://youtu.be/pwIiDn4ShE0|here]] if you have time at the end.)
+<WRAP INFO>
+=== Learning Goals ===
+  * Create an analytic model for a line of charge
+  * Be able to explain how you set up each part of the integral, $dQ$, $r$, limits, etc.
+  * Explain how you used superposition in your solution
+  * Understand how surfaces become charged (particularly as an insulator in this case)
+</WRAP>
+==== Project 4B: Better Thundercloud Model ====
 {{  184_projects:project4b.png?300}}
 The storms over Lakeview have gotten worse, with an almost permanent pitch black cloud system hovering overhead. A new model for the thundercloud needs to be produced to obtain a better understansding of how it is functioning. While they greatly appreciated the model you created last week for the Mapping N$\vec{E}$twork Sensory Array (MNSA), the data they are collecting from the sensors are simply not matching the model's predictions. They have concluded that modeling storm clouds as point charges was, in fact, problematic. Based on some research from the [[184_notes:lightning|National Weather Service]], it looks like a better model for clouds would be two flat sheets of charge since the negative charges in the cloud collect on the bottom of the cloud and the positive charges collect near the top.
@@ Line 82: / Line 97: @@
 </WRAP>
-==== Project 4B: Mini-Particle Accelerator  ====
-S.P.A.R.T.A.N force, still trapped in the town of Lakeview, has been sent as part of a larger governmental team to work on developing a micro-particle accelerator on the outskirts of town. Why does a town the size of Lakeview need a micro-particle accelerator? You are not at liberty to say. Your team is tasked with modeling the initial part of the accelerator, which uses a constant electric field to accelerate the charges. The concept is that the particles will enter a tube that is encapsulated by rings of charge. Your team needs to demonstrate that this concept will produce a __constant__ electric field.
-=== Part 1: ===
-The first bit of code that you have received is from the previous team who were able to construct a single ring of charge and show the electric field due to that ring at some point. Your team should construct the electric field vectors for a circle inside the accelerator (smaller than the ring) at a distance of a few centimeters from the ring face.
-<code>
-GlowScript 2.7 VPython
-#Set up constants
-R = 0.02
-r_obs = 0.05
-Q = 1e-9
-N = 20
-dq = Q/N
-scale=1e-4
-oofpez = 9e9 #1/(4pi epsilon_0) in N m^2/C^2
-#Defining a ring at the origin
-myring = ring(pos = vector(0,0,0), radius = R, axis = vector(0,0,1), color = color.blue, thickness = 0.02*R)
-#Create an empty list for the charges
-ChargeList=[]
-#Set up the step size and angle for creating the charges
-dtheta = 2*pi/N
-theta = dtheta/2
-#Create charges in a circle and add them to the ChargeList
-while theta < 2*pi:
-    rpiece = R*vector(cos(theta),sin(theta),0) #location of piece
-    particle = sphere(pos = rpiece, radius = R/20, color = color.yellow)
-    ChargeList.append(particle)
-    theta = theta + dtheta
-#Create an empty list for the observation points
-ObsList = []
-#Set up the step size and angle for creating the observation points
-phi = 0
-dphi = pi/4
-#Create charges in a circle and add them to the ObsList
-while phi < 2*pi:
-    r_obs_piece = r_obs*vector(cos(phi),sin(phi),1) #location of piece
-    obs_particle = sphere(pos = r_obs_piece, radius = R/20, color = color.red)
-    ObsList.append(obs_particle)
-    phi = phi + dphi
-#Find the electric field at each observation point
-for obs_point in ObsList:
-    for charge in ChargeList:
-        Enet=vec(0,0,0)
-</code>
-=== Part 2 ===
-After you got this initial code working, your team was able to construct a model of a tube consisting of multiple rings, all with the same charge. But, the field doesn't look quite right - it's not constant as expected. Your bosses seem to think the field can be made constant in the tube, so it's up to you to figure out how.
-<code>
-num_points = 10
-num_rings = 11
-N = 11
-spacing = 0.02
-# Set some constants and stuff
-R=0.02 #radius of ring in m
-ax = vector(0,0,1) # simplify things
-Q=1e-9 #charge of ring in C
-oofpez=9e9 #1/(4pi epsilon_0) in N m^2/C^2
-#draw axis
-zaxis=cylinder(pos=-2*R*ax, radius=0.015*R, axis=4*R*ax, color=color.black)
-#draw points
-points = []
-for i in range(num_points):
-    xr = 0.01*sin(i*2*pi/num_points)
-    yr = 0.01*cos(i*2*pi/num_points)
-    points.append(sphere(pos=vector(xr,yr,0.01), color=color.red, radius=5*zaxis.radius))
-#make and draw rings
-rings = []
-ring_charge = [Q,Q,Q,Q,Q,Q,Q,Q,Q,Q,Q]
-for i in range(num_rings):
-    loc = i - (num_rings)//2
-    rings.append(ring(pos=vector(0,0,spacing*loc), radius=R, axis=ax, color=color.blue, thickness=0.02*R))
-# Find net field
-for apoint in points:
-    Enet = vector(0,0,0)
-    for i in range(len(rings)):
-        aring = rings[i] # look at one ring
-        dq = ring_charge[i]/N #charge of a piece
-        dtheta = 2*pi/N #theta increment for our loop
-        theta=dtheta/2 #initial theta for first piece of loop
-        Ering = vector(0,0,0) #net electric field for single ring
-        rpoint = apoint.pos
-        scale=1.2*mag(rpoint)/8000 #used to scale the arrows representing E-field
-        while theta<2*pi:
-            rpiece = R*vector(cos(theta),sin(theta),aring.pos.z/R) #location of piece
-            r = rpoint-rpiece #vector from piece to point in space
-            rmag = mag(r) #magnitude of r
-            rhat = norm(r) #unit vector for r
-            dE = oofpez * dq / rmag / rmag * rhat # Electric field of peice of ring
-            Enet = Enet + dE
-            particle=sphere(pos=rpiece, radius=apoint.radius, color=color.yellow) #draw a particlee
-            theta=theta+dtheta
-    Evector=arrow(pos=rpoint, axis=scale*Enet, color=color.orange, shaftwidth=apoint.radius/2)
-</code>