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

No, not if they have the same mass.

Force=G Massearth*Massstuff/radiusearth^2

No, both will have same force of gravity due to same mass

No, the force of gravity acting on the piece of iron and the piece of wood will be the same if both have the same mass. The force of gravity on an object depends solely on its mass and the gravitational field strength at the location. The gravitational field strength is constant for a given location.

To calculate the force of gravity on an object, you can use the formula:

F = m * g

Where:
F is the force of gravity,
m is the mass of the object, and
g is the gravitational field strength.

Since the mass of both objects is the same, the force of gravity will be the same regardless of the material. The only way the force of gravity could be different is if the objects were located in different places with different gravitational field strengths.

In summary, if both the piece of iron and the piece of wood have the same mass and are located in the same place, the force of gravity acting on them will be equal.