Hello friends:

I'm wondering if anybody can clarify an issue regarding how Pascal's Law is applied to hydraulic presses. According to Pascal, a pressure applied to an enclosed fluid is distributed uniformly throughout the volume of the fluid. In other words, the pressure applied to the fluid in a vessel that contains the fluid will result in that same pressure on any part of the wall of the vessel. For instance, if a piston in a cylinder applies ten pounds per square inch to fluid in the cylinder, then any point of the wall of the cylinder will experience a pressure of ten pounds per square inch.

Now, a hydraulic press is much like the aforementioned vessel, except that it includes a second piston that usually has a larger diameter and hence a larger area than the first piston. The force applied by the smaller piston to the fluid in the cylinder moves the larger piston outward and with greater force than the force applied by the smaller cylinder. The net effect is to amplify the force applied by the smaller cylinder.

The amplification of force is made possible by the fact that since Pascal's Law dictates that the pressure is the same at all points on the wall of the cylinder, then larger areas of the wall experience greater total force. Since the larger piston has a larger area than the smaller piston under the uniform pressure in the cylinder, then the total force on the larger piston must be larger than the force on the smaller piston.

Is that correct?

Jagella