It's correct. Terminal velocity is irrelevant here; it's true outside the atmosphere too. I really am talking about force and acceleration. It's clear that the

It's correct. Terminal velocity is irrelevant here; it's true outside the atmosphere too. I really am talking about force and acceleration. It's clear that there's more force on a heavier object. How much force do you have to apply to counteract a bucket full of rocks from falling to the ground, vs. an empty bucket? Your arm is certainly applying more force to the former. So then the question becomes Why doesn't the full bucket fall faster? Because it has more inertia, and thus it's more difficult to accelerate. But there's also more force, which overcomes this difficulty. The amount of greater force is exactly identical to the greater inertia, so the acceleration remains the same. The "exactly identical" here is no coincidence. https://en.wikipedia.org/wiki/Equivalence_principle https://en.wikipedia.org/wiki/Equivalence_principle