from __future__ import division
from visual import *

#constants
epsz=8.85e-12#C^2/(Nm^2)
oofpez=1/(4*pi*epsz)
dt=1e-2
Qsource=1e-6#Coulombs
Qtest=1e-6#Coulombs
mTest=1e-3#kg

#initial conditions
t=0
rSource=vector(1,2,3)#m
rTest=vector(3,-2,-1)#m
vTest=vector(0,0,0)#m/s


ptclTest=sphere(pos=rTest, color=color.red)
ptclSource=sphere(pos=rSource, color=color.blue)
scriptR=ptclTest.pos-ptclSource.pos
scriptArr=arrow(pos=ptclSource.pos, axis=scriptR, color=color.white)
scene.autoscale=false
while (t<20):
    rate(100)
    scriptR=ptclTest.pos-ptclSource.pos
    scriptRmag=mag(scriptR)
    scriptRhat=scriptR/scriptRmag
    scriptArr.axis=scriptR

    F=oofpez*Qsource*Qtest*scriptRhat/scriptRmag**2
    vTest+=F/mTest*dt
    ptclTest.pos+=vTest*dt
    t+=dt