Re: : Gravity in two directions.

Answer:
It depends on the size of the smaller mass placed in the middle.  

If the smaller mass were very tiny (in comparison to the distance from the 
two larger masses), then the answer would be "nothing would happen". The 
small mass would be in a condition of unstable equilibrium.  If the small 
mass were displaced ever so slightly closer to one of the masses, it would 
accelerate at an increasing rate toward the closer body.

A more interesting thing happens if the mass in the middle is of 
significant size. Tidal forces become apparent due to the uneven forces of 
the pull of gravity caused by different parts of the central object being 
different distances away from the larger bodies.  The force of 
gravitational attraction is inversely proportional to the square of the 
distance between the objects. This uneven pull of gravity, called a 
gravitational force gradient, can stretch the body out if not held together 
tightly.  In a real sense, these tidal forces (if the bodies were large 
enough and close enough) could cause the breakup of all three bodies even 
before they collided.