MECHANICAL ADVANTAGE

The illustration of Messrs. Davey & Co. shews the experimental
working stresses on the various parts of a tackle with a loaa of 1 ton.
The pull on the hauling part may be found approximately from the

general formula, but it is evident that the f stress will vary on all
parts^ with the speed of hoisting or lowering. Let us apply the
formula and compare our answers with the tested loads given in
the illustration.