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Stonehenge

Stone shifting 4

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According to the paper "Science and Stonehenge" the angle is 70 degrees, in the experiment the sledge fell between the ramp and the stone increasing this angle.

Some quick calculations on the weighted rope.

Initially the gearing is so high that the rope has to sag under the weight of the stone. As it does, the gearing reduces. Eventually a point will be reached where the tension in the rope balances the weight, or the weight reaches the ground first (in which case its work is done).

To get some idea of the numbers involved, I calculated a case where the rope has sagged to the point where the weight is just about to touch the ground and that all the forces are then in balance. With a monolith sticking 24 feet out of the ground and a rope 100 feet long, the gearing is about 2.5:1. It starts much higher than this when the rope is almost straight, so the monolith cannot resist the initial pull. We would therefore need a weight of about 3 tons (allowing for the fact that the rope is not pulling perpendicular to the monolith).

If we can raise a 40 ton stone to a height of 16 feet, it should be easy-peasy to raise a 3 ton stone 10 feet in the air. I estimate that we'd need to do it twice to get the stone to vertical from 70 degrees.