Question for physics guys

Gaius · 2023-03-06T04:01:03.496Z

On how large a scale could this be duplicated?

Can we suspend a kid, or a bicycle or a garden shed from an unnailed board
lying on a flat roof (or or in a tree)?

Gaius · 2023-03-06T04:08:17.208Z

According to this a 2x4, set on its edge can hold 300lbs.
(Two of them can hold 600 lls I guess.)

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So, if this works as in the video, we could build a large version of this with ordinary lumber and hold something very large. right?

e7alr · 2023-03-06T04:30:43.572Z

It could be done to scale, but it wouldn’t be a durable hanger, Done outside it would be even more unstable due to atmospheric inputs.

Gaius · 2023-03-06T04:54:29.004Z

e7alr:

It could be done to scale, but it wouldn’t be a durable hanger, Done outside it would be even more unstable due to atmospheric inputs.

Cool, but it might be good for a college stunt
(like hanging a small car off the administration building), right?

e7alr · 2023-03-06T05:38:23.161Z

Not seeing it.

Samm · 2023-03-06T06:04:59.669Z

Gaius:

On how large a scale could this be duplicated?

To any scale you like, as long as the materials and connections are strong enough to accommodate the load you select.

Bill.in.PA · 2023-03-06T14:16:48.254Z

The real issue is center of gravity of the bottle.

The center of gravity has to be under the table in order for the match to hold the bottle. Otherwise, the match simply tilts up and falls as shown at the beginning of the video. The added matches push back the attachment point for the string, so the bottle is hanging under table.

Swinging the bottle side to side does not affect the stability as shown at the end of the video. On the other hand, allowing the bottle swing forward so that the center gravity is no longer under the table causes it to fall.

Samm · 2023-03-06T21:44:45.764Z

Correct. All that diagonal match does is to transfer the force that supports the free end of the match on which the weight is hung to the center of gravity of the weight. That depends on the shear connections between the ends of the cross match and the cords carrying the weight of the bottle. It would be easier to explain if I could draw up and post this as a force diagram.

FloridaYankee · 2023-03-07T11:58:25.805Z

Stocking hanger1200×1200 109 KB

zantax · 2023-03-07T14:13:51.314Z

FloridaYankee:

Stocking hanger1200×1200 109 KB

Helps to think of it as the bends not being there, no mystery when you realize the weight is directly below the support. As far as gravity is concerned the outward bends aren’t there.

Gaius · 2023-03-07T15:12:45.349Z

Sooo
this can work on any scale too?

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