A water tank is filled to a depth of 10 m and the tank is 20 m above ground. The water
pressure at ground level in a hose 2 cm in diameter is closest to:
A) 3.9 × 105 N/m2
B) 2.0 × 104 N/m2
C) 9.2 N/m2
D) The cross-sectional area of the tank is needed.
rho g h = 1000 (9.81)(30) = 2.94*10^5
add 1 atm = 1*10^5
and get total of 3.9 * 10^5
Thank you boss!
Why do you need to add the 1 atm? And the 2 cm in this question does not matter?
Because the air we live in also has pressure
no pressure change in a horizontal hose with no flow through it.
To calculate the water pressure at ground level in the hose, we can use the hydrostatic pressure formula, which is P = ρgh.
In this formula:
- P represents the pressure in Pascal (Pa).
- ρ represents the density of the fluid, which is water in this case. The density of water is approximately 1000 kg/m3.
- g represents the acceleration due to gravity, which is approximately 9.8 m/s2.
- h represents the height of the water column above the point where we want to calculate the pressure.
Given:
- The depth of the water in the tank is 10 m.
- The tank is 20 m above the ground.
To find the pressure at ground level, we need to calculate the height of the water column above ground level. This can be done by subtracting the depth of the water in the tank from the total height of the tank.
Height of water column above ground = Total height of the tank - Depth of water in the tank
= 20 m - 10 m
= 10 m
Now we can calculate the water pressure at ground level:
P = ρgh
= 1000 kg/m3 * 9.8 m/s2 * 10 m
= 98000 N/m2
The water pressure at ground level in the hose is approximately 98000 N/m2.
However, none of the answer choices provided match this value. It seems that the cross-sectional area of the tank is needed to calculate the correct answer.