Simulating N-Body Gravity Interactions: A Challenge in Computational Physics

[DrCheeto]

Homework Statement

Hi for fun, and to understand physics better I have scripted a program that replicate gravity exerted from one force (ex the Earth rotating around the sun) and it works well. But now I want to have mutliple bodies that affect gravity and using the same equations it isn't working. To find net gravity I am just finding the force of gravity between say Earth and sun1 and sun2 then adding them up clearly this is wrong because it does not work at all.

Homework Equations

Here is my equations

        'Force
        Ftmp = (G * Ball.Mass * Planet.Mass) / (nDist * nDist)
        Force.X = Ftmp * (Ball.Pos.X - Planet.Pos.X) / nDist
        Force.Y = Ftmp * (Ball.Pos.Y - Planet.Pos.Y) / nDist
        
        'Acceleration
        Acceleration.X = Force.X / Ball.Mass
        Acceleration.Y = Force.Y / Ball.Mass
        
        'Velocity
        Ball.Velocity.X = Ball.Velocity.X + Acceleration.X
        Ball.Velocity.Y = Ball.Velocity.Y + Acceleration.Y
        
        'New Position
        Ball.Pos.X = Ball.Pos.X - Ball.Velocity.X
        Ball.Pos.Y = Ball.Pos.Y - Ball.Velocity.Y
        
        'Return new information
        Gravity = Ball

The Attempt at a Solution

My attempt was basically this

for ncount = 1 to 3
        Ftmp = (G * Ball.Mass * Planet(ncount).Mass) / (nDist * nDist)
        Force.X = force.x + Ftmp * (Ball.Pos.X - Planet(ncount).Pos.X) / nDist
        Force.Y = force.y + Ftmp * (Ball.Pos.Y - Planet(ncount).Pos.Y) / nDist
next

 

[DrCheeto]

Can anyone help me?