Above is a very odd block-and-tackle configuration. Odd, as in has-no-practical-use. But rather than waste it, we’ve made it this week’s Puzzle: What mechanical advantage does this configuration have?
Assume that the sheaves have no friction, that all leads are parallel, and that equal force is exerted, straight down, on both tackle ends (arrows). The uppermost block will move toward the deck.
You don’t need to explain your answer in order to win, but as long as you get the purchase number right, your explanation doesn’t have to make sense, so hey, go for it.
Bonus points if you can approximate the maximum range of motion, up and down, of the uppermost block. Assume that the fiddle block is one foot long, and that the tackles end at the arrows.
Send your entry to firstname.lastname@example.org. The winner will be randomly selected from the pool of correct entries. Deadline for entries is noon Pacific time, Monday, March 19th.
This week’s Fabulous Prize is an autographed first edition of Kaci Cronkhite’s wonderful best-seller, Finding Pax. You can find out more about this wonderful book here
Note: Painter Frank Hanavan recently posted our Puzzle’s photograph, from Petersson’s book on ship model rigging. It appears to be a nice enough book, but the image, as near as I can tell, shows a configuration that has never been found outside the pages of that book. If such is not the case, please let me know.