How does Hydraulic Press stop so fast after shaterring something? Why isn’t there any momentum?
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Think of it like a screw. You’re turning a screw, tightening a clamp down on a coffee mug, until it shatters, but the screw stays right where it was.
This is because liquids are **functionally** incompressible. The idea of hydraulic pressure is partially a misnomer. That pressure isn’t stored in the system like a compressed gas or a spring. It’s like that screw. The pressure reading on the gauge tells us its instantaneous working pressure, or the force being delivered to the load, as a function of kPa, Bar, or PSI present in the fluid. You can see it linger if the load is pushing back on the cylinder, sometimes called clamping force, but it will instantly disappear the moment it clears the load.
They do not surge forward because a) the fluid in the rear of the cylinder, which was pushing forward, cannot be compressed and stores no energy. When the load disappears, the system is already at equilibrium. It cannot drop, because the liquid also cannot be put into a vacuum but for a few microseconds and immediately nulls out. And b) there is fluid in the front of the cylinder, used to retract it, which is also preventing the piston from traveling forward (in the case of double acting cylinders, which most YouTube Crushing Stuff presses are). This is much the same as how the threads of a screw prevent movement in both directions, unless the screw is turned.
Fluid power transmission gets very eli10 as you keep looking. I can explain more if you have more questions
Edit: yes, you can compress liquids in the realm of physics, but this explanation was too long already as it was.
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