英文:
I'm building this double bouncing ball simulation with vpython and am running into a weird rubber banding issue
问题
I understand that you want a translation of the provided code snippet. Here is the translated code:
# 这是图形
##################################################
g1 = graph(xtitle="t 展开收缩", ytitle="y [m]", width=500, height=150)
fp = gcurve(color=color.green)
g2 = graph(xtitle="t 展开收缩", ytitle="v [m/s]", width=500, height=150)
fv = gcurve(color=color.red)
g3 = graph(xtitle="t 展开收缩", ytitle="E [J]", width=500, height=150)
fK = gcurve(color=color.blue)
fU = gcurve(color=color.red)
fE = gcurve(color=color.magenta)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
g4 = graph(xtitle="t 展开收缩", ytitle="y [m]", width=500, height=150)
fyA = gcurve(color=color.green)
fyB = gcurve(color=color.orange)
##################################################
#定义弹跳的地板
#//////////////////////////////////////////////////////////////////////////////////////////
R = 0.02
floor = box(pos=vector(0,-0.005-R,0), size=vector(0.1,0.01,0.1))
#//////////////////////////////////////////////////////////////////////////////////////////
#一些基本参数/初始条件
##################################################
h = .3
#g = vector(0,-9.8,0)
g = 9.8
c = 0.5
t = 0
dt = 0.01
bt = 0
#球的定义
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
mA = 2
x0A = 0
y0A = h
vx0A = 0
vy0A = 0
dtA = 0.01
btA = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#球2的定义
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
mB = .05
x0B = 0
y0B = h + .1
vx0B = 0
vy0B = 0
dtB = 0.01
btB = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
##################################################
#定义一个球
#//////////////////////////////////////////////////////////////////////////////////////////
ball = sphere(pos=vector(0,h,0), radius=R, color=color.green, make_trail=True, trail_type="points",
interval=10, retain=10)
ball2 = sphere(pos=vector(0,h,0), radius=R, color=color.orange, make_trail=True, trail_type="points",
interval=10, retain=10)
#//////////////////////////////////////////////////////////////////////////////////////////
#球的物理
##################################################
#t<x; x定义了多少秒
while t < 2:
#rate(x); x定义了更新速率
rate(10)
#球的基本物理方程
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
xA = x0A + vx0A * btA
yA = y0A + vy0A * btA - .5 * g * btA**2
vxA = vx0A
vyA = vy0A - g * btA
vA = sqrt(vxA**2 + vyA**2)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#球2的基本物理方程
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
xB = x0B + vx0B * btB
yB = y0B + vy0B * btB - .5 * g * btB**2
vxB = vx0B
vyB = vy0B - g * btB
vB = sqrt(vxB**2 + vyB**2)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#根据生成的矢量定义球的新位置
#/////////////////////////////////////////////////////////////////////
ball.pos = vector(xA, yA, 0)
ball2.pos = vector(xB, yB, 0)
#/////////////////////////////////////////////////////////////////////
#球弹跳物理
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#pos.y<x; x定义了球弹跳的高度
if ball.pos.y < -0.005 - R:
#球弹跳矢量变化
#/////////////////////////////////
vyA = -sqrt(c) * vyA
vxA = sqrt(c) * vxA
vy0A = vyA
vx0A = vxA
x0A = xA
y0A = yA
#/////////////////////////////////
bt = 0
btA = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#pos.y<x; x定义了球弹跳的高度
if ball2.pos.y < -0.005 - R:
#球2弹跳矢量变化
#/////////////////////////////////
vyB = -sqrt(c) * vyB
vxB = sqrt(c) * vxB
vy0B = vyB
vx0B = vxB
x0B = xB
y0B = yB
#/////////////////////////////////
bt = 0
btB = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
if ball.pos.y >= ball2.pos.y: ##
vyA = -sqrt(c) * vyA
vxA = sqrt(c) * vxA
vy0A = vyA
vx0A = vxA
x0A = xA
y0A = yA
#/////////////////////////////////
bt = 0
btA = 0
if ball2.pos.y <= ball.pos.y: ##
#球2弹跳矢量变化
#/////////////////////////////////
vyB = -sqrt(c) * vyB
vxB = sqrt(c) * vxB
vy0B = vyB
vx0B = vxB
x0B = xB
y0B = yB
#/////////////////////////////////
bt = 0
btB = 0
if vyA <= 0.01:
vyA = 0
if vyB <= 0.01:
vyB = 0
#如果ball2.pos.y < = ball.pos.y:
#更新图形和时间
#/////////////////////////////////
K = .5 * mA * (vxA**2 + vyA**2)
U = mA * g * yA
E = K + U
fp.plot(t, yA)
fv.plot(t
<details>
<summary>英文:</summary>
Im trying to make a pair of balls bounce in 1D space and let them colide. I'm running it on glowscript which uses webVPython, should be the same as VPython from what I can tell.
I keep running into this issue where the balls tend to rubber band causing some weird collision issues where they can slowly phase through other objects, also I'm too stupid to figure out how to calculate the momentum change, not sure if thats relavent to the rubber banding but if anyone knows an eqation I could use or a fix that would be appricated.
link to code: https://www.glowscript.org/#/user/amirdmgazzali/folder/bouncingballs/program/bouncingballs1
this is the code:
\` Web VPython 3.2
#these are the graphs
###############################################################################################
g1 = graph(xtitle="t 展开收缩",ytitle="y [m]", width=500, height=150)
fp = gcurve(color=color.green)
g2 = graph(xtitle="t 展开收缩",ytitle="v [m/s]", width=500, height=150)
fv = gcurve(color=color.red)
g3 = graph(xtitle="t 展开收缩",ytitle="E [J]", width=500, height=150)
fK = gcurve(color=color.blue)
fU = gcurve(color=color.red)
fE = gcurve(color=color.magenta)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
g4 = graph(xtitle="t 展开收缩",ytitle="y [m]", width=500, height=150)
fyA = gcurve(color=color.green)
fyB = gcurve(color=color.orange)
#g5 = graph(xtitle="t 展开收缩",ytitle="y [m]", width=500, height=150)
#fyB = gcurve(color=color.red)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
###############################################################################################
#defining a floor to bounce on
#//////////////////////////////////////////////////////////////////////////////////////////
R = 0.02
floor = box(pos = vector(0,-0.005-R,0),size=vector(0.1,0.01,0.1))
#//////////////////////////////////////////////////////////////////////////////////////////
#some basic perameters/initial conditions
###############################################################################################
h = .3
#g = vector(0,-9.8,0)
g = 9.8
c = 0.5
t = 0
dt = 0.01
bt = 0
#ball definitions
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
mA = 2
x0A=0
y0A=h
vx0A=0
vy0A=0
dtA = 0.01
btA = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#ball2 definitions
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
mB = .05
x0B=0
y0B=h+.1
vx0B=0
vy0B=0
dtB = 0.01
btB = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
###############################################################################################
#defining a ball
#//////////////////////////////////////////////////////////////////////////////////////////
ball = sphere(pos=vector(0,h,0), radius=R, color=color.green, make_trail=True, trail_type="points",
interval=10, retain=10)
ball2 = sphere(pos=vector(0,h,0), radius=R, color=color.orange, make_trail=True, trail_type="points",
interval=10, retain=10)
#//////////////////////////////////////////////////////////////////////////////////////////
#physics behind the ball
###############################################################################################
#t<x; x defines how many seconds
while t<2:
#rate(x); x defines update rate
rate(10)
#just the basic physics equations for the ball
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
xA = x0A + vx0A*btA
yA = y0A + vy0A*btA - .5*g*btA**2
vxA = vx0A
vyA = vy0A - g*btA
vA = sqrt(vxA**2 + vyA**2)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#just the basic physics equations for the ball2
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
xB = x0B + vx0B*btB
yB = y0B + vy0B*btB - .5*g*btB**2
vxB = vx0B
vyB = vy0B - g*btB
vB = sqrt(vxB**2 + vyB**2)
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#defines ball new position based of the generated vector
#/////////////////////////////////////////////////////////////////////
ball.pos = vector(xA,yA,0)
ball2.pos = vector(xB,yB,0)
#/////////////////////////////////////////////////////////////////////
#ball bounce phyics
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#pos.y<=x; x defines the height at which the ball bounces
if ball.pos.y<-.005-R:
#Ball bounce vector changes
#/////////////////////////////////
vyA = -sqrt(c)*vyA
vxA = sqrt(c)*vxA
vy0A = vyA
vx0A = vxA
x0A = xA
y0A = yA
#/////////////////////////////////
bt = 0
btA = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#pos.y<=x; x defines the height at which the ball bounces
if ball2.pos.y<-.005-R:
#Ball2 bounce vector changes
#/////////////////////////////////
vyB = -sqrt(c)*vyB
vxB = sqrt(c)*vxB
vy0B = vyB
vx0B = vxB
x0B = xB
y0B = yB
#/////////////////////////////////
bt = 0
btB = 0
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
#\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
if ball.pos.y>=ball2.pos.y: ##
vyA = -sqrt(c)*vyA
vxA = sqrt(c)*vxA
vy0A = vyA
vx0A = vxA
x0A = xA
y0A = yA
#/////////////////////////////////
bt = 0
btA = 0
if ball2.pos.y<=ball.pos.y: ##
#Ball2 bounce vector changes
#/////////////////////////////////
vyB = -sqrt(c)*vyB
vxB = sqrt(c)*vxB
vy0B = vyB
vx0B = vxB
x0B = xB
y0B = yB
#/////////////////////////////////
bt = 0
btB = 0
if vyA<=0.01:
vyA=0
if vyB<=0.01:
vyB=0
# if ball2.pos.y<=ball.pos.y:
#updates graph and time
#/////////////////////////////////
K = .5*mA*(vxA**2+vyA**2)
U = mA*g*yA
E = K+U
fp.plot(t,yA)
fv.plot(t,vyA)
fE.plot(t,E)
fK.plot(t,K)
fU.plot(t,U)
fyA.plot(t,vyA)
fyB.plot(t,vyB)
t = t + dt
btA = btA + dt
btB = btB + dt
bt = bt + dt
#/////////////////////////////////
###############################################################################################
#prints time
print("t = ",t ,"seconds")`
</details>
# 答案1
**得分**: 1
Your program is way too (overly) complex to make it feasible to figure out what might be going wrong. I urge you to abandon using kinematics formulas to update positions. Here is a much simpler scheme: https://www.glowscript.org/#/user/Bruce_Sherwood/folder/Examples/program/00Demo/edit, where you calculate the net force F on an object and update an object's momentum as ball.p += F*dt and update the object's position as ball.pos += (ball.p/ball.m)*dt. You can detect collisions by finding that the distance between centers of the two balls is less than the sum of their radii. Note that a better place to ask about Web VPython is the forum https://groups.google.com/g/glowscript-users
<details>
<summary>英文:</summary>
Your program is way to (overly) complex to make it feasible to figure out what might be going wrong. I urge you to abandon using kinematics formulas to update positions. Here is a much simpler scheme: https://www.glowscript.org/#/user/Bruce_Sherwood/folder/Examples/program/00Demo/edit, where you calculate the net force F on an object and update an object's momentum as ball.p += F*dt and update the object's position as ball.pos += (ball.p/ball.m)*dt. You can detect collisions by finding that the distance between centers of the two balls is less than the sum of their radii. Note that a better place to ask about Web VPython is the forum https://groups.google.com/g/glowscript-users
</details>
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