Hi
I need to know how much ground water presuure would be required to lift a 1.200m diameter plastic tank weighing 650kg out of the ground please,
Please supply the answer in Kpa or psi
Cheers
How is the cylinder oriented? Axis pointing down?
Yes
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The oreientation of the tank needed to be specified. The ground water gauge pressure at the bottom multiplied by the cylinder area must equal the weight, neglecting friction at the sides.
P*pi*D^2/4 = 650 kg*(9.8 m/s^2)
P = 5630 N/m^2 = 5.6 kPa
Ground water gauge pressure will be determined by the length of the cylinder. This assumes that the tank is above the aquifer. Otherwise there will be no ground water pressure.
Hi Drwls
If the tank is standing up i.e 1.200 dia x 1.100 high with 650 kg inside, would the water pressure to lift it be the same
Cheers
To calculate the groundwater pressure required to lift a plastic tank out of the ground, we can use the concept of buoyancy. Buoyancy force is the upward force exerted on an object submerged in a fluid, such as water.
Here are the steps to calculate the groundwater pressure:
Step 1: Calculate the weight of the displaced water
The weight of the displaced water is equal to the weight of the tank. In this case, the weight of the tank is 650 kg.
Step 2: Calculate the volume of water displaced
The volume of water displaced can be calculated using the formula for the volume of a cylinder, V = πr²h, where r is the radius of the tank (0.600m) and h is the height of the tank (assuming it is completely buried underground).
Step 3: Calculate the density of water
The density of water is approximately 1000 kg/m³.
Step 4: Calculate the pressure required
The pressure required can be calculated using the equation P = (W/V), where P is the pressure, W is the weight of the displaced water, and V is the volume of water displaced.
Now, let's perform the calculations:
Step 1: The weight of the tank is given as 650 kg.
Step 2: The volume of water displaced can be calculated as follows:
V = πr²h
= π(0.600m)²h
Since the height of the tank is not provided, we cannot calculate the exact height. However, if we assume that the tank is fully buried, we can use the diameter of the tank (1.200m) as the height.
= π(0.600m)²(1.200m)
≈ 1.356m³
Step 3: The density of water is approximately 1000 kg/m³.
Step 4: The pressure required can be calculated as follows:
P = (W/V)
= (650 kg) / (1.356m³)
≈ 478.94 kg/m³
To convert the pressure from kg/m² to KPa or psi, we can use the following conversion factors:
1 kg/m² = 9.81 Pa
1 Pa = 0.001 KPa
1 Pa = 0.000145 psi
So, the calculated pressure of 478.94 kg/m³ can be converted to the desired units using the appropriate conversion factors.
Please note that the assumption of the tank being fully buried and the height of the tank being equal to the diameter are reasonable, but if the actual conditions are different, the results may vary.