Physics question - surely it's just the extra weight?

[Ari]

Got shown this the other day.

http://www.youtube.com/watch?v=X-QFAB0gEtE

Thing is, for all his explanation of the one of the chain hitting the ground sooner due to the chain "whipping the weight around thus making it accelerate faster", surely the real reason is that the one with the chain on hits the ground first simply because it has a blimmin great heavy chain attached to it so it's heavier?

Or am I just being thick? (Again).

[Ari]

Ledaig said:

Irrespective of mass, everything will accelerate at the same rate 9.81m/s^2.

Something to think about is that during the fall the chain will be building up a store of energy as it's velocity increases, as each link in the chain reaches the end of it's permitted travel this energy will be transformed into an alternative form - in this case applied as an additional accelerative force to the remaining length of chain in free fall as well as the weight.

So if the chain is accelerating at the same rate as the dumbell, each link won't be reaching the end of its travel, it'll all be static relative to each other surely?

[Ari]

deadtom said:

I think its kinda related to the feather vs hammer scenario; in this situation both objects have more or less the same atmospheric drag, however the chained weight has more effective mass, meaning the force is greater (F = MA, or in this case Ma where a acceleration due to gravity at earth's surface), so it overcomes the atmospheric drag more easily.

That's kind of how I see it, attaching a length of heavy chain pulls it down quicker.

But the video suggests it's something to do with the chain on the other side of the loop somehow exerting an upward force.

I just can't see it...