Suppose the piston in hydraulic lift has a cross-sectional area of 0.10 m2. a. What air pressure must be produced by the air compressor to support 14,000 N, the combined weight of car and lift? b. Why is the area of the liquid surface in the reservoir irrelevant, yet the cross-sectional area of the piston very relevant?
P F/A 14000/0.1 140000 Pa since the force is supported by piston, its area is more significant!!
Physics question: fluids - hydraulic lift? Suppose the piston in hydraulic lift has a cross-sectional area of 0.10 m2. a. What air pressure must be produced by the air compressor to support 14,000 N, the combined weight of car and lift? Pressure is caused by a force pushing or pulling on the surface of a substance. Pressure is the force on each square meter of the surface of a substance. Pressure Force ÷ area Pressure 14,000 ÷ 0.10 140,000 N/m^2 b. Why is the area of the liquid surface in the reservoir irrelevant, yet the cross-sectional area of the piston very relevant? The VERTICAL surface of the reservoir holding the water in the reservoir. The HORIZONTAL top surface of the liquid in the reservoir is not pushing on the VERTICAL surface of the reservoir. The VERTICAL surface of the liquid in the reservoir is pushing on the VERTICAL surface of the reservoir
Pressure is a measure of force per unit area, so to determine the pressure needed to balance a force of 14kN over an area of 0.10 m^2, use the simple formula: p F/A 14,000/0.10 140,000 N/m^2 (or 140,000 Pa 140 kPa) The area of the reservoir does not matter because the pressure will be the same throughout the entire reservoir no matter what the cross-sectional area is, and there is no load within the reservoir. As for the piston, however, when dealing with loads/forces, the force exerted by the fluid depends on the cross-sectional area over which the pressure acts (see formula above). For a given pressure, the force exerted by the fluid increases as cross-sectional area increases. Hope this helps!
