Question

is the force of gravity stronger on a piece of iron than on piece of wood if both have same masses?

Answer 1

As the gravitational force depends upon mass of earth, mass of object and square of radius of earth.
As it doesn't depend on size of object, there will be no change on their gravitational pulls.

Answer 2

Both have same gravitational pull because gravity depend on mass of object ,earth and radius and mass of both are equal so they exert equal gravity