from visual import *
scene=display(title="ball drop",x=0, y=0, width=800,
              height=600,range=vector(10000,10000,10000),
              center=vector(0,0,0))
t = 0.0
C = 0.8 #<- This is our drag coefficient
dt = 0.1
m = 70
a = vector(0.0,0.0,0.0) # This is our acceleration
A = 3.14159*0.4*0.4
rho = 1.2
s = vector(0.0, 5000.0, 0.0)
v = vector(0.0,0.0,0.0)
g = vector(0.0,9.8,0.0)
ball = sphere(pos=s,radius = 200, color = color.blue)
balllabel = label(pos=ball.pos,text = 'Vy=%1.2f' %v.y,
                  xoffset=-100,yoffset=0)
balllabel2 = label(pos=ball.pos,text='Distance Fallen = %1.2f' %s.y,
                   xoffset=100,yoffset=0)

while t < 50:
    rate(50)  # This slows down the computer to 50 frames per second
    fnet = 0.5*C*rho*A*vector(0,mag2(v),0)-m*g # <-- Current force on skydiver
    a = fnet/m # <-- current acceleration on skydiver
    v = v + a*dt
    s = s+v*dt
    ball.pos=s
    balllabel.pos=s
    balllabel.text='v=%1.2f m/s' %v.y
    balllabel2.text='Vertical Position=%1.1f m' %(s.y)
    print 't=',t , '    s=',s, '  v=',v
    t = t + dt