[DuncanWaring]

The hammers greater mass has greater gravitational pull on moon.

That's true, but the "greater gravitational pull" is balanced by that fact that there's a greater mass to be accelerated.

[cripplecreek]

Also true.

You could move a supermassive black hole with a feather if you could anchor the feather somehow and had a few billion years to do it in.

[SampleMan]

That's true, but the "greater gravitational pull" is balanced by that fact that there's a greater mass to be accelerated.

Negative. All mass has the same reaction to gravitational forces, inertia and force are linear. 1000 lb takes more to get moving than 100 lb, but there IS more to get it moving.