Tuesday, August 9, 2011

Pascal Application

Car can be easily lifted by hydraulic lift in garage is the example application of Pascal law. Another example is disc brake. The principle of these things are Pascal Law, that the pressure between two surfaces are same, thus bigger surface will have bigger force.


Hydraulic lift (Halliday Resnick: Fundamental Of Physics)
As we can see at the picture, surface area A1 is smaller than A2. Based on Pascal law, pressure at A1 and A2 are same. Pressure is force divided by area, P=F/A, thus force needed to lift the car will be much smaller than the weight of car.
    
Small force F1 makes pressure at A1, this pressure is transmitted to A2. The pressure work at A2 makes force with upward direction. The force produced in A2 will be much bigger than force applied F1. This is why car whose weight is very heavy can be lifted easily.

The same principle is also used in brake system, in this case is disc brake system. When brake handle is pulled with certain force, it will transmit pressure to another surface at other edge, and makes force to clamp disk. This disc is attached to the wheel, since the rotation of disc is de-accelerated thus the speed of vehicle also becomes slower.

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