Problem 11: (6 points) PS 13-23: The output piston of a hydraulic press has a cr
ID: 2039170 • Letter: P
Question
Problem 11: (6 points) PS 13-23: The output piston of a hydraulic press has a cross-sectional area A. (a) How much fluid pressure is needed to produce a force F on the output piston? (VS) (b) If the area of the input piston is 0.20 A, what force is needed on the input piston to produ a force F on the output piston? (VS) (c) Calculate the input force needed to produce an output force of 1.5 106 N for a 0.25 output piston. (NS) Problem 12: (8 points) PS 13-6: A rectangular block of length I, width w, and total height h floats in water with only a height y submerged under water, as shown. (a) What is the weight of the block? (VS) (b) What is the density of the block? (VS) (c) Calculate the weight and density of a block 1-25.0 cm long, w= 15.0 cm wide, ar h 11.0 cm high that floats with y -9.0 cm of the block submerged. (NS)Explanation / Answer
11. (a) Fluid pressure needed, P = force/area = F/A .
(b) By Pascal's law, pressure at input piston = pressure at output piston
Let F' be the required force needed to apply on the input piston to have a force F on the output piston, then, by Pascal's law, we have,
F'/0.2A = F/A
=> F' = 0.2 F
Thus required force = 0.2F
(c) Input force needed = (0.2×1.5×10^6) N = 3×10^5 N