1. What is the difference between a separation vector ($\vec{r}$) and a separation unit vector ($\hat{r}$)?
2. Draw an arrow for the E-field on the ground from a positive storm cloud. Draw an arrow for the E-field on the ground from a negative storm cloud. Where does the “tail” of each E-field arrow start? What direction does each arrow point?
3. Read through the main question and look at the given code block. Read through the code line-by-line as a group and write out in plain English words (or pseudocode) what each line does. For example “Line 3 - makes a cloud as a white sphere”

The team back at headquarters has just received a call from the National Weather Service (https://www.weather.gov/) that they want you to take some additional data on this cloud. Apparently the cloud is behaving strangely. It is staying together longer than most clouds do and is moving northward, which is not typical of most clouds in this geographical region (see some discussion of this here if you're interested). Someone in town has started a rumor that the cloud is unnatural, and the mayor is demanding the S.P.A.R.T.A.N. team look into it with the new Super-Mega-Storm-Cloud-Meter 9000^TM. For the moment, the winds have died down and the cloud isn't moving.

The Super-Mega-Storm-Cloud-Meter 9000^TM, standing 30 m tall, operates by collecting data from the cloud using a series of satellite dishes on the ground that monitor the cloud as it moves and develops/deteriorates, sort of like a fancy digital multimeter. There is only one problem: the equipment you are going to use to collect said data is extremely sensitive, specifically to electric field interference. In order to collect useful data, it must be properly calibrated to the source of interest. The field team has already set up the device below the cloud 250 m away from HQ. In order to calibrate this instrument, a computer model of the electric field of the cloud needs to be created and sent to the measuring device's main computer, located with the field team. This allows them to correct for any background “noise” in the data caused by satellite dishes, cell phones, camera equipment, power lines, transformers, interference with any residual charges in the ground, etc. Thankfully, your team has a template for building these computer models.

Complete the computer model that will calibrate the Super-Mega-Storm-Cloud-Meter 9000^TM to the cloud's electric field at the position of the meter. Once that is working, the Super-Mega-Storm-Cloud-Meter 9000^TM will also need a variety of electric field positions (at the satellite dishes on the ground) to the North and the South of its operation point once it has been properly programmed for its stationary position. This is to set a baseline for collecting data as the cloud begins moving.

GlowScript 2.9 VPython
## Scene Setup
scene = display(width=1000, height = 1000)

## Parameters
ec = 1.6e-19
k = 9e9

## Objects
cloud = sphere(pos=vec(0,3500,0), color=color.white, radius=100)
ground = box(pos = vec(0,0,0), width=5000, length=5000, height=0.1, color=vec(1,0.7,0.2))
HQ = box(pos = vec(-250,100,0), width = 10, length=10, height=200, color=color.green)
detector = box(pos = vec(0,30,0), width = 5, length=5, height=3, color = color.white)

#Step 1: Make one E-Field Arrow
E = vec(0,0,0)
field = arrow(pos=detector.pos, axis = E, color = color.yellow)


#Step 2: Make multiple E-field Arrows
starting_point=-200

while starting_point<200:
    
    E=vec(0,0,0)
    field = arrow(pos=detector.pos, axis = E, color = color.yellow)
    
    starting_point=starting_point+150

Using Python

Getting Started with Glowscript

Common Commands in Python

1. How do you know if your code is working right? (Write these in your evaluation quadrant!)
2. What does the while loop do in Step 2? How do you know what should be inside the loop vs outside the loop?
3. What happens to your arrows if you change different parameters in the code? Try it out! (e.g. cloud height, cloud charge, etc.)
4. How big is the E-field below the cloud? Is that large/small/normal for an E-field?
5. What direction does the separation vector point? What about the E-field?
6. What assumptions did you need to make to simplify this problem?