Bouncing_Balls.ipynb

Kernel: Python 2 (Ubuntu Linux)

The following example comes from the VPython documentation at http://vpython.org/contents/docs/VPython_Intro.pdf. It demonstrates how to create a box with walls that a single ball can bounce around inside of.

Take a look at the code and see if you can figure out what each part does.

from vpython import *

L = 5.0
thickness=0.2
wall_Top = box (pos=vector(0,  L, 0), size=vector(2*L, thickness, 2*L),  color = color.blue)
wall_Bottom = box (pos=vector(0, -L, 0), size=vector(2*L, thickness, 2*L),  color = color.blue)
wall_Left = box (pos=vector(-L, 0, 0), size=vector(thickness, 2*L, 2*L),  color = color.red)
wall_Right = box (pos=vector( L, 0, 0), size=vector(thickness, 2*L, 2*L),  color = color.red)
wall_Back = box(pos=vector(0, 0, -L), size=vector(2*L, 2*L, thickness), color = color.red)

ball = sphere (color = color.green, radius = 0.5, make_trail=True, retain=50, 
               trail_color=color.green)
ball.mass = 1.0
ball.p = vector(0.2, .3, .4)

L=L-ball.radius

dt = 0.5
t = 0.0
tf = 300.0


while t<tf:
    rate(40)
    ball.pos = ball.pos + ball.p/ball.mass*dt
    
    ### Detect wall collisions
    if ball.pos.x>L or ball.pos.x<-L:
        ball.p.x = -ball.p.x
    if ball.pos.y>L or ball.pos.y<-L:
        ball.p.y = -ball.p.y
    if ball.pos.z>L or ball.pos.z<-L:
        ball.p.z = -ball.p.z
        
    t = t + dt   #Update time