This section is from the book "Applied Science For Metal Workers", by William H. Dooley. Also available from Amazon: Applied Science For Metal Workers.
A jack screw has a single thread, seven turns to the inch, and a handle 18 in. long. If a force of 50 lbs. is applied to the end of the handle what weight can be lifted, neglecting friction?
(Take π. = 22 / 7.)
 
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