1. The problem statement, all variables and given/known data The handle of a hydraulic jack is 15 cm long and is pivoted 2.5 cm from the input piston which has a radius of 0.60 cm. The output piston has a radius of 1.2 cm. What weight could be lifted by the jack if the person pushing on the handle is to exert no more than 110 N of force? http://edugen.wiley.com/edugen/courses/crs2216/cutnell3550/ssg/cutnell3255c11/image_n/nw0002-y.jpg 3. The attempt at a solution Silly question...I doubt I'm right, as I'm hardly an authority to go up against a text book. But that being said... I'm confused as to why the textbook (Cutnell & Johnson Physics Study Guide 7th ed.) says that F is positive when F1 is negative? They're both pointing down...so...aren't they both negative??? F2 is positive and pointing upwards, that makes sense. But why F is also positive completely eludes me... Am I missing something completely obvious? On a side note - I hope I'm not violating any copyright laws by posting that diagram. I just want the answer, not a prison term!