A piston of cross-sectional area "a" is used in a hydraulic press to exert a small force of magnitude "f" on the enclosed liquid. A connecting pipe leads to a larger piston of cross-sectional area A. (a) what force magnitude F will the larger piston sustain without moving? (b) If the piston diameters are 3.80 cm and 53.0 cm, what force magnitude on the small piston will balance a 20.0 kN force on the large piston? A picture of the figure can be found at http://panda.unm.edu/Courses/Price/Phys160/F33-3.jpeg I used the formula f/a = F/A for (a). the answer I found was F = f x 195. Am i supposed to leave f in my answer. If no, how do i solve for f. I used the same formula for (b) and got 102. Please help me double check my answers.
Seems to be correct. In the first Q, you just have to write fA/a, I think, because the values are given only in (b).