Sharper cord angle bears double the beam's weight
A caution to test by experiment, and the angle-to-load proportion
A large triangular figure fills the sheet: from a pulley at the top-left apex a family of curved and straight cords fans down to a horizontal beam, with a weight hanging at the corner. The text first warns that the figure must be checked against experiment before any judgement is drawn from it, then states the proportion: the more acute a cord's angle to the beam, the more of the beam's weight it bears. Worked out, if cord f r carries 2 of the beam's weights, cord a f, at half the angle, carries 4.
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Test the figure by experiment before judging it
Before drawing any conclusion, Leonardo insists the figure be returned to experiment; only then may one judge anything further about it.
Half the angle, double the load: cords a f and f r
The rule is quantified with the cords' angles. As the angle a goes twice into the right angle r, cord a f bears twice what cord f r bears: if f r supports 2 of the beam's weights, a f supports 4.
