Climbing a Ladder in a Pipe (April 2026 Challenge Question)

The ladder will rotate about its center. As long as she stands with her feet below the center, she should be ok.

Let me clarify a bit.

Assume she stands on a step 5 feet 9 inches from the bottom of the ladder and keeps her balance (continues to stand vertically). If the ladder rotates in the pipe, it would lift the lady's weight against gravity as the step traces an arc of radius 3 inches. The equilibrium position would be with the lady standing at the lowest point of this arc.

She must balance herself on a step closer to the bottom of the ladder.

I doubled the picture size. You can see two fasteners, left and right in the image.

Place the top of one leg of the ladder against the outside of the fastener you are not working on. It does say 12 foot tunnel and 12 foot ladder, so it should touch. Climb the ladder keeping your center of gravity on your side of the center of the ladder.

Surely the worker should forget the ladder and use a mobile scaffold.

After all there is no way to maintain the angle needed for the base offset 1/3, (4FT) to the height of the ladder (12FT), Has one ever tried to safely to climb a vertical ladder, I have tried to climb a 40ft ladder placed in the back of a ute against a power station wall and let me tell you even with an offset it is not for the faint hearted.

Even turning the ladder side on will nor save the worker from a fall but then one should buy shares in a medical facility.

1. The ladder will rotate counterclockwise with the offset weight of the worker, until it is essentially horizontal in the pipe.

2. She summons her coworker who is a similar weight, to hold the rungs near the upper half of the ladder, changing position to offset the rotating effect of the worker as she ascends.

As soon as the worker starts climbing, the center of gravity of the system worker+ladder will shift away from the center or rotation. The resulting torque will cause the ladder to turn, until the combined center of gravity happens to be beneath the rotation point. After crossing that point, there will be a torque in the opposite direction. Making the story short, the system will behave as a pendulum, which will not stop oscillating given that there is no friction and assuming that the worker is not moving in a funny way.

If the worker continues to climb, then the oscillations will become faster and faster, since the frequency of a pendulum is governed by the length of it; in our case, the length between the rotation point and the worker. Now, if the worker ever manages to pass the rotation point, then the whole system will reverse its orientation. Not good either.

In order to avoid such a troubling effect, the worker should climb from the side, so that each leg steps on alternate sides of the ladder. That's only if the ladder is not about to fall on its side (I assume that since it is as long as the tube's diameter, the two legs lock in place to prevent it to move sideways).

Now that I think of it, the worker won't be able to reach the ceiling, since 12ft (or 6ft from the center of rotation) is beyond the reach of the hand. Therefore, the worker will have to stand stepping right on the rotational axis (so that the ladder does not reverse). If there is a ladder step right at that point, or a little below it, then the worker will be able to reach the ceiling.

The question is how much of acrobatic skills are required in order to stand up like this. I guess that as soon as the worker extends her body upwards, she could have time to grab from the point she is supposed to fix. I assume that this point - unlike the rest of the tube - causes a certain amount of friction, otherwise it couldn't be fixed!

12 feet do not fit inside of 12 feet. I've tried.

The simplest way is to turn the ladder diagonally inside of the pipe and climb the edge of the ladder. The diagonal is longer than the pipe is tall, so it will not slip, it will wedge itself against the wall and the ribs inside of the pipe.

Call your next case.

The image provided…

The AI generated image cannot be relied upon as a reliable source of any conditions of the challenge.

In the image, I make the worker to be about 7 foot 10 inches tall.

In fact she wouldn't be able to get the ladder into the position shown, unless she put it in to the end of pipe that way. So, fortunately the solution would become obvious to her when she reached the fasteners.

If she tries to put the ladder up with its vertical axis at right angles to the position shown, it will jam just before it gets to vertical. She then just needs to climb with the ladder leaning away from her, and keep her C of G to her side of bottom of the ladder.

Anyone who has tried to climb a ladder with its foot too close to the bottom of the wall will see how this works straight away.

Looks like the perfect scenario for a slap-stick film.

All that's needed is the addition of a bucket of whitewash!

Did anyone read my reply at #14

She would not be able to get the ladder into the position shown, or, any position with the rungs parallel to the axis of the pipe: unless she put it in the end of the pipe like that, and then, good luck with trying to manoeuvre along any length of pipe. (See A.)

If however she tried to stand it up with the rungs at a right angle to the axis of the pipe, it would jam just before reaching vertical. (See B and ZOOM.)

In C I have shown the angle that the ladder would jam at by extending the lines from the top and bottom of the ladder in B then fitting a 12 foot line.

The rectangle I have used to represent the ladder is 12 foot long, and, 15 inches wide.

Needless to say that she could easily keep her C of G to her side of the bottom of the ladder whilst climbing it jammed as in C.