184_projects:sorting_hawkions_24 [Projects & Practices in Physics]

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
===== Project: Sorting Hawkions =====

==== Kick Off Questions ====
  - What is the equation for magnetic force? Like all forces, a force always acts from something on something. For the magnetic force equation, this is the magnetic force from what on what?
  - How is the right hand rule for magnetic field different from the right hand rule for magnetic force?
  - Read through the problem and code below. Comment each line of the given code. In particular, what does the "if statement" at the bottom of the code do?

==== Main Problem ====
Director Lewis calls you, very excited.  She says that one of the FTOE scientists, Dr. Paul Triste, has developed a theory that the Hawkions could be used to dispel the storms around Lakeview!  Since your team was so successful at creating the magnetic field detector, Director Lewis wants your help to take some final measurements to confirm his theory.  

The Hawkions appear to have a variety of masses, so they need to start by trying to sort the particles by mass for further analysis, using a mass spectrometer. Before building it, your team is asked to develop a model of the spectrometer.  The lab director has specified that they would like to use a constant magnetic field of 2 T and to isolate the effects of the B-field within the magnetic housing box, but they are unsure what direction the magnetic field should be relative to the catching plate. Below is the beginning of a model that was developed by another team before they mysteriously disappeared.

<code python>
GlowScript 3.0 VPython


## Model parameters
B = vec(0,0,0)

## Objects
mag_housing =  box(pos=vec(1,0,0), length=2, height=2, width=2, opacity=0.2)
catchingplate = box(pos=vec(4,0,0), length=0.1, height=10, width=10, opacity=1)
xaxis = cylinder(pos=vector(-3,0,0), axis=vector(6,0,0), radius = 0.05, color=color.white)
yaxis = cylinder(pos=vector(0,-3,0), axis=vector(0,6,0), radius = 0.05, color=color.white)
zaxis = cylinder(pos=vector(0,0,-3), axis=vector(0,0,6), radius = 0.05, color=color.white)


## Set up particles (DO NOT EDIT LIST)
i = 0
N = 20
particleList = []

while i < N:
    
    particleList.append(sphere(pos=vec(-2-4*random(),0,0), radius = 0.1, m = 20*(random()+1), v = vec(2,0,0), q = 10, color=color.red))
    i = i + 1

## Calculation Loop
t = 0
dt = 0.01

while t < 30:
    
    rate(300)
    
    for thisParticle in particleList:
        
        thisParticle.pos = thisParticle.pos + thisParticle.v*dt
    
        
        if thisParticle.pos.x > catchingplate.pos.x:
        
            thisParticle.v = vector(0,0,0)
        
    t = t + dt
</code>

<WRAP Info>
=== Learning Goals ===
  * Use the right hand rule to relate the charge's velocity and external magnetic field to the force on that charge.
  * Use circular motion to relate the radius of the particle's trajectory to it's force
  * Understand what an "if statement" does in the code
</WRAP>

==== Wrap Up Questions ====
  - Which of your particles are the heavier particles and which are the lighter ones? How do you know?
  - What would create a constant magnetic field? (Like the one given in the code?)
  - Why do you get circular motion for the particles?
  - Do the particles speed up or slow down as they go through the magnetic field? Do the particles have an acceleration?
  - How would you calculate the magnetic force on a charge? (Pick an magnetic field & charge velocity and do a sample calculation)
  - Suppose you had two particles that were different isotopes of carbon. One particle is a Carbon-12 atom that is singly ionized, and the other particle is a Carbon-14 atom that has been singly ionized. If both particles are sent through a slot with a speed of 56.3 m/s into a 3 T magnetic field  (shown below), where would they land?

{{  184_notes:img_3396.jpg?600  }}