IIT JEE , AIEEE Forum - Physics , Mechanics

gauravstud

water stands at a depth D behind the vertical upstream face of a dam. how 2 find the line of action of the eq. resultant force.

ashish_banga

the line of action will be into the vertical upstream face . we can find line of action if we remove the wall where the water will go

krishna.gopal

Let us take top surface of water as x=0 and bottom as x=d. Let width of Dam wall be W.

Consider a thin strip of thickness dx at x=x. It experiences a pressure og

gx or a force(dF) =

gxWdx. This will have a moment of force about x=0 given by dF*x=

gx²Wdx .

Position of line of force =

_{[ 0]}

^{[D ]} (xdF)/_{[ 0]}^{[D ]} (dF)=2D/3

So resultant force acts at a deapth of 2/3 below surface

shipra22_bhardwaj

line of action will b into vertical upstraem ans will b at the depth of 2/3 below the surface pls rely if ans is not correct

krishna.gopal

Depth of line of action will be 2/3D.But what do you mean by vertical upstream. It will be horizontal perpendicular to dam wall.