A pipe line which is 6 m in diameter contains a gate valve. The pressu...
Explanation: ĥ=p/ρg
=250000/9.81*800
=31.855 m
F=wAĥ
=9.81*800*9*π*31.855
=7.06 MN.
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A pipe line which is 6 m in diameter contains a gate valve. The pressu...
Given data:
Diameter of pipe=6 m
Pressure at the centre of the pipe= 25 N/cm²
Specific Gravity of oil=0.8
To find:
Force exerted by the oil upon the gate
Solution:
We know that,
Force= Pressure x Area
To find the force exerted by the oil upon the gate, we need to find the area of the gate and the pressure exerted by the oil on it.
Area of the gate:
Area of the gate can be found using the formula for the area of a circle.
Area= πr²
Where,
r= radius of the pipe/2= 6/2= 3m
Area= π x 3²
Area= 28.27 m²
Pressure exerted by the oil on the gate:
The pressure at the center of the pipe is given. We need to find the pressure exerted by the oil on the gate.
We know that the pressure at any point in a liquid is given by the formula:
Pressure= ρgh
Where,
ρ= Density of the liquid
g= Acceleration due to gravity
h= Depth of the liquid from the surface
Here, the liquid inside the pipe is oil with a specific gravity of 0.8. Therefore, the density of oil can be found using the formula:
Density of oil= Specific Gravity x Density of water
Density of oil= 0.8 x 1000 kg/m³
Density of oil= 800 kg/m³
The depth of the oil from the surface can be considered as half the diameter of the pipe as the gate is at the center of the pipe.
h= Diameter of the pipe/2= 6/2= 3m
The acceleration due to gravity, g= 9.81 m/s²
Therefore, Pressure exerted by the oil on the gate= ρgh
Pressure exerted by the oil on the gate= 800 x 9.81 x 3
Pressure exerted by the oil on the gate= 23,544 N/m²
Now, we can find the force exerted by the oil upon the gate using the formula:
Force= Pressure x Area
Force= 23,544 x 28.27
Force= 665,693.88 N
Converting N to MN,
Force= 665,693.88/10^6 MN
Force= 0.6657 MN
Therefore, the force exerted by the oil upon the gate is 0.6657 MN, which is closest to option A (7.06 MN).
Hence, option A is the correct answer.