0
$\begingroup$

Say we have a door oriented in an oblique way and there's a fluid above it and nothing below it . The question is to find the hydrostatic force acting on the door . In class, we calculated it by integrating the pressure of fluid times a surface element of the door(dS). The direction of force is along the normal of the surface. But thinking intuitively the pressure of the fluid varies vertically with height and not oblique as to match the normal of the surface . So our force should not be normal to the surface . It should however push the door downward and not along its normal. But by calculation its just normal . Any help ?

$\endgroup$
1
  • $\begingroup$ gravity acts down. $\endgroup$
    – JMLCarter
    Oct 24, 2017 at 15:25

1 Answer 1

0
$\begingroup$

Gravity acts downward.

If, though, the water were free to move and was deflected by the door, the force it experienced would then be in the direction of its change in velocity.

$\endgroup$
1
  • $\begingroup$ What if the water wasn't free to move , and it was given an external push downwards, then the door might be shifted along its normal and also along the given push. Shouldn't it move only in its normal direction? Why does it change in the case of the external push? $\endgroup$
    – user65035
    Apr 8, 2018 at 15:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.