**Little Nemo **nailed the best approach. It doesn’t require the middle person to support a crazy amount of weight and it solves the dynamic balance problem the OP’s picture conveniently ignores.
The only issue with it is that it requires be beam be long enough to allow for off-centering the middle person and still have people firmly planted on both sides of the gap. There are beam lengths which are long enough to bridge the gap, but too short to adjust the leverage enough to make this approach work.
The graphic is inaccurate as it depicts a female iron worker. A buddy of mine was an iron worker in Pittsburgh and he tells me there wasn’t a single female in the union, at least at that time. Their dress is incorrect as well.
Silly, they’re not iron workers, those are the suits coming up to check on the progress and tell the workers how to do their job correctly and more effectively.
No, silly, you can definitely tell they’re either management or engineer/consultants, because they have clean white hard hats, with no stickers or anything.
Without that evidence, the female could indeed be an actual worker – they do exist – but of course that’s not the way to bet.
Well gravity doesn’t instantly cancel out any velocity you had previously either.
Given that the gap looks about 1.5 metres (maybe less), I think not only would it be trivial to jump it, I think if you were sprinting forward and weren’t even aware of the gap you would trip / stumble your way across it. But I haven’t done the calcs…
You wouldn’t be able to jump it with the beam on your shoulder and the other two people having their arms wrapped over the top of it. You could try, but it wouldn’t work very well.
To get back to the OP, a better example of teamwork would be if a bricklayer at the other side had put down his trowel for a moment to help. The beam is pushed forward with the middle and rear people bunching together a bit at the back. Bricklayer supports the front of the beam, and then the first two members can lift feet as needed. My one question becomes the last member. Would three at the other end allow the beam to be supported and stable enough to act as a cantilever?
Well, yes you’d have to jump a bit; you can’t just keep running straight. But as a former long-jumper I definitely got much farther in Long Jump than in Standing Broad Jump. At 100mph a flick of the big toe would send you forward enough to bridge that gap. (Good luck stopping without breaking a bone though.)
Wow, “jump” is one of those words that gets really weird if you use/think about it too much.
If the beam was flexible (like a vaulter’s pole) and dynamically wobbling with the middle person at the harmonic point, then perhaps you could time the gap crossing with the pole wobble so that each person is ‘bounced’ over the gap as the beam flexes…
If each person was strong enough to support the weight of the beam and the two other individuals this should be no problem.
You could make a similar demonstration with lego. Take a lego beam, add 3 sets of wheels evenly spaced, and roll it across a gap whose width is the exact same as the distance between two adjacent axles. It should roll over it just fine.
Nope … instead of crouching, he’d just be lifting his legs, since he’s not carrying any load. If he pushes against the ground at all, that pushes the first person down, like a teeter-totter.
Of course, the act of his pulling his legs up moves his center of gravity up, which momentarily increases his downward force on the beam, causing the other guy to swing up a bit. Of course, eventually he’ll reach equilibrium and start to pendulum down. So, I don’t recommend this unless you have the timing worked out.
Think more closely about this. The only things you accomplish by moving the fulcrum are:
a) making sure the person over the hole doesn’t swing down
b) increasing the load on the fulcrum
Both happen because the end person on the land is not lifting the beam, he’s pulling down on it. With two people supporting a beam with single point of contact each, there’s no way for two to help in supporting a third who’s on either end. Only the guy in the middle gets supported by two people.
Let’s look at this real-life.
Let’s assume all are equal weight (not required but makes the math easier) and the person in the middle has their shoulder under the center of mass as the fulcrum. As the lead person steps over the gap, the total torque is zero which as others point out is very unstable.
BUT what if the woman in the middle moves her hand backwards enough to create a moment arm and pulls down on the beam? Now the torque will hold the guy in front up and help the guy in back stay down.
Wow, “jump” is one of those words that gets really weird if you use/think about it too much.
