(07-06-2017, 09:16 PM)Ken S Wrote: What fascinates me with simple machines is how adaptable they can be. My telephone block and tackle had double pulleys on each end. That was a good balance for our work. If two more pulleys were added to each side, much more rope would be required for the same amount of movement, however, the amount of weight which can be moved increases incredibly.
We can choose the bevel angle which suits our needs, in both wedges and in knives. That's part of the allure of sharpening over the ages.
Yes, Ken, you are correct! They are only six classical simple machines which use leverage to multiply force or change its direction.
Ignoring friction losses, the work done on the load is equal to the work done by the applied force.