fluids help

[pizza1994]

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across and opening 50 m wide , dam A holds back a body of water that is 100 m deep. Across an opening 100 m wide , dam B holds back a body of water that is 50 m deep, which dam experiences a total greater force on its surface?

the answer is Dam A but I dont get it.

These are from the wikipremed website

 

[DrknoSDN]

A simple explanation is that the pressure from the deeper part of the deeper dam exerts more force on the surface of the dam than the wider portion of the wider dam.

Basically compare the lower 1/2 of the tall dam to one side of the wide damn.
The lower half experiences more force from the water pressure when compared to half of the shallow wide damn.

You can do that because the shape is the same and only differs in orientation, also the top half of the tall dam could be viewed as an individual segment that is 50x50m and experiences a force idential to one side (1/2) of the wide damn, which is just two 50x50 sections that are side by side.

 

[pizza1994]

A simple explanation is that the pressure from the deeper part of the deeper dam exerts more force on the surface of the dam than the wider portion of the wider dam.

Basically compare the lower 1/2 of the tall dam to one side of the wide damn.
The lower half experiences more force from the water pressure when compared to half of the shallow wide damn.

You can do that because the shape is the same and only differs in orientation, also the top half of the tall dam could be viewed as an individual segment that is 50x50m and experiences a force idential to one side (1/2) of the wide damn, which is just two 50x50 sections that are side by side.

but isnt the area of A and area of B come into account?

 

[el_duderino]

Average pressure across dam A is higher than average pressure across dam B. 50m avg depth pressure times 500 sq m vs 25m avg depth pressure times 500 sq m.

Same surface area, greater average depth.

 

[pizza1994]

Average pressure across dam A is higher than average pressure across dam B. 50m avg depth pressure times 500 sq m vs 25m avg depth pressure times 500 sq m.

Same surface area, greater average depth.

right so you are saying they both have the same surface area which is 500 cubic meters. P=F/A and so because A is the same we just look at the pressure term and because we know pressure depends on depth and because A has a greater depth than B then it overall has greater force?

is this right?

 

[el_duderino]

Yup.

 

[pizza1994]

Yup.

epic thanksss!!!!!!