Tidal forces can break apart objects that orbit too close to a planet, producing rings like those of Saturn. Consider an asteroid 600km in radius, 65mm from Saturn's center.
What's the difference in gravitational acceleration between the two sides of the asteroid?
f=GMsat*Mast [( 1/65mm)^2-1/65.6mm)^2]
There is another way, using differentials.
we don't know the mass of the astroid, how do we use the equation you have provided?