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A 10 ft diameter by 15 ft height vertical tank is receiving water (p 62.1 lb/ cu ft) at the rate of 300 gpm and is discharging through a 6 in ID line with a constant speed of 5 fps. At a given instant, the tank is half full. Find the water level and the mass change in the tank 15 min later.

User SergeyT
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Final answer:

The water level in the tank 15 minutes later is approximately 15.16 ft. The mass change in the tank 15 minutes later is approximately 37,337.7 lb.

Step-by-step explanation:

To find the water level and the mass change in the tank 15 min later, we need to consider the flow rate and the dimensions of the tank.

The tank has a diameter of 10 ft and a height of 15 ft. Using the formula for the volume of a cylinder, we can calculate the initial volume of water in the tank:

Volume = π * (radius)^2 * height

Given that the diameter is 10 ft, the radius is 5 ft. Substituting the values into the formula, we get:

Volume = 3.14 * (5 ft)^2 * 15 ft = 1177.5 ft³

Therefore, the initial volume of water in the tank is 1177.5 ft³.

Since the tank is half full, the initial volume of water is half of the total volume:

1177.5 ft³ / 2 = 588.75 ft³

Now, we can calculate the flow rate:

Flow Rate = 300 gpm = (300 gallons / 7.48 gallons/ft³) / 1 min = 40.11 ft³/min

15 minutes later, the additional volume of water in the tank is:

Volume = Flow Rate * Time = 40.11 ft³/min * 15 min = 601.65 ft³

Adding the initial volume and the additional volume, we can find the total volume of water in the tank after 15 minutes:

Total Volume = Initial Volume + Additional Volume = 588.75 ft³ + 601.65 ft³ = 1190.4 ft³

The water level can be calculated by dividing the volume by the area of the base of the tank:

Area of Base = π * (radius)^2 = 3.14 * (5 ft)^2 = 78.5 ft²

Water Level = Total Volume / Area of Base = 1190.4 ft³ / 78.5 ft² = 15.16 ft

Therefore, the water level in the tank 15 minutes later is approximately 15.16 ft.

The mass change in the tank can be calculated using the density of water:

Mass Change = Density * Volume

Given that the density of water is 62.1 lb/ft³, we can calculate the mass change:

Mass Change = 62.1 lb/ft³ * 601.65 ft³ = 37,337.7 lb

Therefore, the mass change in the tank 15 minutes later is approximately 37,337.7 lb.

User Chirag Nagariya
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