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Comment by tomp | Hacker News Reader

A steel wirte isn't lifting anything, it's just holding.

But a steel wire can be reeled in using a reel. And if we don't include the airpump required for these origami muscles in our "muscle weight" then we don't need to include the winch weight in the case of the reeled wire.

Only counting the steel wire in the winch example is unfair in the other direction. You have to count a small part of the winch (pulley?) for it to be directly comparable.

But this is all incredibly silly, and what we all agree on is that they fail to consider the vacuum pump, valves and reinforced vacuum hoses in order to make their invention seem fancier.

The proper comparison is not with the pulley, the wire or the winch, but rather the structure holding the pulley up.

i don't understand what this means. you understand that g = 9.81 m/s^2 ... every second? the difference between colloquial lifting and just holding is a matter of applying on the order of just 1% more force.

There is a difference between a material’s chemical bonds resisting the acceleration of gravity and actually being able to lift an object from one height to a second, higher height.

I'm not talking about force, but about energy. To hold something suspended in air, you don't need any energy. But a steel wire can't lift anything, you need to have a motor (or muscle) that actually expends energy to move the object higher.

A steel wire can lift things all by itself. Just cool the wire. If you disagree with this, consider the motor or hydraulic cylinder that can't lift anything either. (Without an external source of energy like a battery or compressor.)

I'm half serious about this. The other main "artificial muscle" technology is nichrome wire after all.

So if we took away 1% of that 1000x it's own weight it would be able to lift it? It can't. It will never be able to. Only thing I got out of my engineering dynamics class - ropes don't lift. Well, that and jokes about couple moments.

A lift is not a hold. A human can hold a ton of weight against gravity, but that's not them lifting it. See the squat. You can put a huge amount of weight on your back compared to the amount you can actually move. If you put them on an escalator, they could probably even move a distance with it. But that isn't them lifting it that distance.

A human can hold several loaded shipping containers stacked upon each other against gravity.

The human will be very flat and leaking all over, but it will be holding the containers.

"I guess he kind of bench pressed that steam roller... kind of."

He lifted it several millimeters off the ground!

as someone who stalls out at the midpoint of a squat coming up very often i can tell you that locking your knees with weight on your back is not holding anything - it's putting your posterior chain under compression. my point was that something like a barbell hold (like this http://www.myfitnessstudio.co.uk/wp-content/uploads/barbell-...) is just as hard as just curling.

You mean infinity more force, since at rest (holding) no force is being applied at all.

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