text: what is liquid pressure and pascal's law of hydraulics? application of pascal's law a liquid is said to be in equlibrium when no net external force acts on it.but in equlibrium condition its molecule as always are in random motion.these hav some maas and hence momentum(mxv).if now we assume an imaginary surface in liquid.these molecule collide with the surface an hece momentum change.rate of change of momentum is force.and force on that particular area is pressure(f/a).this pressure is manifested as liquid as liquid pressure pascal law states that if external pressure is exerted on any part of liquid then it is equally transmitted throughout the liquid.suppose we consider 2 points at same depth(at same depth pressure is equal).point 1 has surface area a and 2 has surface area b,then if f force acts on a(i.e.pressure=f/a) then this pressure will be transmitted to 2.since area of 2 is b so force experienced be f'(pressure=f'/b).now mathamatically              f/a=f'/b