This sound like one of those silly questions. Like which weighs more? a bag containing 1000 lbs of feathers or a bag containing 1000 lbs of iron? ANSWER ; the bag containing the feathers as it would be much larger than the other bag.
Actually, not a silly question. For a bag to be capable of holding 1000 pounds of iron, it would have to be much stronger (thicker, heavier material, whatever) than a bag holding 1000 pounds of feathers. Therefore the answer is probably unknown.
Rather than ask this of Sheldon, I suspect it would be better to ask Penny after a couple of glasses of wine. The answer would likely be consistent with the importance of the question.
Gerry