Body.java in programe

Body.java

public class Body

{

    private Vector r;     

    private Vector v;     

    private double mass;  

    public Body(Vector r, Vector v, double mass)

   {

        this.r = r;

        this.v = v;

        this.mass = mass;

    }

    public void move(Vector f, double dt)

   {

        Vector a = f.times(1/mass);

        v = v.plus(a.times(dt));

        r = r.plus(v.times(dt));

    }

    public Vector forceFrom(Body b)

   {

        Body a = this;

        double G = 6.67e-11;

        Vector delta = b.r.minus(a.r);

        double dist = delta.magnitude();

        double F = (G * a.mass * b.mass) / (dist * dist);

        return delta.direction().times(F);

    }

    public void draw()

   {

        StdDraw.setPenRadius(0.025);

        StdDraw.point(r.cartesian(0), r.cartesian(1));

    }

}