Point mass gravitational problem

[nns91]

Homework Statement

1. A point mass m1= 2kg is at the origin and a second point mass m2=4kg is on the x-axis at x=6m. Find the point on the x-axis for which g=0

Homework Equations

g= -Gm/r^2

The Attempt at a Solution

So g=0 means that g1+g2=0. I set up that 2(r2)^2= -4(r1)^2 and made r2=x-6 and r1=x.

Thus, I have a quadratic equation as x^2 -4x+12=0 which has no solution. I am wrong on this question. How should I fix this ??

 

[robphy]

What would g=0 mean?

 

[nns91]

gravitational field.

 

[robphy]

Is the gravitational field a vector field?