JEE Physics
JEEPhysicsMechanical Properties of FluidsClass 11

How does a small hydraulic jack let one person lift a whole car?

By Pascal's law, pressure applied to an enclosed fluid is transmitted equally everywhere.

By Pascal's law, pressure applied to an enclosed fluid is transmitted equally everywhere. So P = F1/A1 = F2/A2, giving F2 = F1 × (A2/A1). Push with a small force on a small piston, and a large piston with (say) 50× the area pushes back with 50× the force. You trade distance for force — the big piston moves only 1/50th as far.

Key point

F2 = F1 × (A2/A1): a bigger output piston multiplies the force.

Common mistake

thinking force is created for free — the large piston moves a much smaller distance.

Memory tip

Pascal's law multiplies force by area ratio, conserving work.

Tap to watch or see it right here — the app stays open (it only opens a quick search if nothing embeddable is found).

More on Mechanical Properties of Fluids