Suggest why the hydraulic press does not work properly if the oil contains bubbles of air.
GCE O-level 5059 Physics 2015 November Paper 2 Question 4(b)(i)
1) Inefficient - Work done by piston with effort is more than work done by piston with load (because some work done to compress the gas).
2) Pascal principle - Pressure at piston with effort will not be equal to the pressure at piston with load.
3) Time lag - The piston with load will take some time to move after the effort is being exerted.
Note: Point 2 can be deduced from point 1. And I believe all these points might not be valid when we use the hydraulic press quasi-statically after it has reached dynamic equilibrium (pressure of gas = pressure of surrounding liquid).
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