第7堂課

# -*- coding: utf8 -*-
# 匯入視覺化套件
from vpython import *

#  1. 畫面設定
# 畫布
scene = canvas(center=vector(0, 0.3, 0.2), background=vector(0.5,0.6,0.5))
# 桌面
table = cylinder(pos=vector(0,-0.03,0), axis=vector(0,-0.01,0), radius=0.7, texture = textures.wood)
# 圓心
center = cylinder(pos=vector(0, -0.03, 0), axis=vector(0, 0.03, 0), radius = 0.007)
# 球
ball = sphere(pos=vector(-0.5,0,0), radius=0.03, color=color.blue)

#  2. 設定參數、初始值
ball.v = vector(0, 0, 0.5)
r = mag(ball.pos)
print("速度 = ", mag(ball.v))
print("時間週期 = ", 2*pi*r/ mag(ball.v))
# 時間間隔
dt = 0.001

#  3. 運動部分
while True:
    rate(1000)

    # 更新球的資料
    ball.a = - (mag(ball.v)**2 / r) * (ball.pos/r)
    ball.v = ball.v + ball.a*dt
    ball.pos = ball.pos + ball.v*dt