# Pressure,Pascals Law [duplicate]

Lets say that i have 2 different types of containers, one cuboidal and another one conical. and lets say both these are massless and fully contain water.

**1.**In the cuboidal one the pressure exerted by liquid column at base is Densitygheight.This multiplied by Area of base will give the force exerted on base.As the container is massless total downwards force is also same.And now by calculating volume and density of liquid , we can find mass of liquid and multiplying by 'g' gives total downwards force.In this case total downward force calculated by both the methods is equal.

**2.**In the conical container, the total downwards force calculated using densitygheight and multiplying by conical container's base area is 3 times greater than the force calculated using volume and density relationship(As the volume is 1/3*height*area).Why is it different, which method is correct to calculate downward force? Why is it so?

• The pressure (Pascal's Law) is given by the weight of the column of water above the measuring point: $p=\rho gh$. The shape of the container doesn't enter into it although the shape can limit the maximum depth of the measuring point.
– Gert
Nov 26, 2015 at 17:28
• Not exactly but yeah partly same, because i also want to know which is right method to calculate total downward force? Nov 27, 2015 at 15:14

• The force on a surface due to a pressure is exerted perpendicular to the surface. The downward component will have to include a $\cos(\theta)$ term. For an upright cone standing on its tip, this will be a constant factor.