[WithinReason]

You can disprove this idea even in a simple thought experiment, you don't even need an actual experiment. If I take 2 large stones, connect them with a string so it's 1 object, will that object fall twice as fast than the 2 stones fall separately?

[cogman10]

Working under the theory that large dense things fall faster than small things, you'd expect that the large stone would drag the small stone. Much like if you attach a piece of wood to a rock with a rope and throw it in water, the rock will drag the wood down.

You'd probably argue that even though they are connected with a string they are still 2 things and there's a density gap between the two of them.

Now, if you try and figure out what makes a thing a thing, it starts breaking down. But if you've already have the working theory, then making an explanation isn't terribly hard.

[Mikhail_K]

That will depend on the length of the rope, once aerodynamic effects are taken into account

[WithinReason]

length is negligible