from visual import *
scene = display(x=0, y=0, height=400, range=10)
scene.up = vector(0,0,1)
scene.forward = vector(0,-1,0)

ball = sphere(radius=1.0, color=color.cyan)
ball.pos = (0.0,0.0,1.0)
ball.velocity = vector(0, 0, 1.0)
ball.accel = vector(0, 0, -9.8)

dt = 0.01
t = 0.0
e = 1.0
b = 0.01
m = 1.0

while t < 10:
    rate(200)
    ball.pos = ball.pos + ball.velocity * dt
    ball.accel = vector(0, 0, -9.8)-(b/m)*ball.velocity.mag*ball.velocity
    ball.velocity = ball.velocity + ball.accel * dt

    if ball.pos.z < 0:
        ball.velocity = -e* ball.velocity
        print('抵抗なしX= -0.039939999999999455,抵抗ありX=',ball.pos.z)

    t = t + dt