## Planet path using netwon's law with forward method

BabyMilo

### BabyMilo (view profile)

님이 질문을 제출함. 18 Feb 2012
최근 활동 Michael

### Michael (view profile)

님이 편집함. 16 Oct 2013
Given the initial position (ie x1,y1) and the velocity (ie vx,vy) of the planet.
How to plot a graph of the path of the planet around the center point (0,0) assuming the center is Earth, using time step of 10s for 500000s?
formula for forward method:
x(t+dt)=x(t)+v(t)*dt
v(t+dt)=v(t)+a(t)*dt
a=GM/r^2
G = 6.67e-11, M = 5.97e24
Many thanks.

James Tursa

### James Tursa (view profile)

18 Feb 2012
What code do you have so far?
Walter Roberson

### Walter Roberson (view profile)

18 Feb 2012
Where is "r" defined?
If I recall correctly, this kind of forward prediction is unable to handle the orbit of Mercury, which has notable influence from drag of the rotational gravitational frame.
James Tursa

### James Tursa (view profile)

19 Feb 2012
@Walter: Well, OP has Euler's method listed which isn't going to do all that great with *any* orbit.

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## 답변 수: 1

Gregory Vernon

### Gregory Vernon (view profile)

님의 답변 19 Feb 2012

You should look into velocity verlet methods.

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