Calculate mass of tank floating in freshwater

In summary, this conversation discusses calculating the mass of a rectangular tank that contains 6L of freshwater and floats upright in freshwater. The tank has a floor area of 0.3m^2 and the bottom is 150mm below the surface of the water. The formula F=P*A=pgAh is used to find the mass of the tank, which is 45kg. It is noted that the mass of the tank and water together is 45kg, but the mass of just the tank is 39kg. The formula for calculating the mass of the tank is density=mass/volume, which is used to find the mass of the tank without the water.
  • #1
Parsifal1
61
3

Homework Statement


A rectangular tank contains 6L of freshwater, has a floor area of 0.3m^2 and floats upright in freshwater. If the bottom of the tank is 150mm below the surface of the water, calculate the mass of the tank.

Homework Equations


F=P*A=pgAh

The Attempt at a Solution


1000*9.81*0.3*0.15=441.54N 441.45/9.81=45kg
 
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  • #2
Parsifal1 said:
A rectangular tank contains 6L of freshwater... calculate the mass of the tank.
I think you're expected to find the mass of just the tank( excluding the water).
 
  • #3
billy_joule said:
I think you're expected to find the mass of just the tank( excluding the water).
That's what I don't understand, 6L=6Kg, should it be mass=0.03*1000=mass*density?
 
  • #4
You've found the mass of the tank and water in post #1; 45kg.
If there's 6kg of water in the tank, how much does just the tank weigh?
 
  • #5
billy_joule said:
You've found the mass of the tank and water in post #1; 45kg.
If there's 6kg of water in the tank, how much does just the tank weigh?
-15Kg? How can the mass of the tank and the water weigh less than the water? Am I using the right formula for the mass of the tank+water?
 
  • #6
Should I do 0.3*0.15*1000=P=pyh=45 Then take 45 from 60? I get the wrong answer by doing that? :/
 
  • #7
If the weight of the water displace=buoyant force, then is the mass of the tank the buoyant force over 9.81? As the mass of the object is equal to the mass of water displaced.
 
  • #8
I found the answer:

density=mass/volume
mass=density*volume
1000*(0.3*0.15)=45
45-6=39Kg

Thanks for the help.
 

1. How do you calculate the mass of a tank floating in freshwater?

To calculate the mass of a tank floating in freshwater, you will need to know the density of freshwater, the volume of the tank, and the weight of the tank when empty. The formula for calculating mass is: mass = density x volume. So, you will multiply the density of freshwater (1000 kg/m3) by the volume of the tank in cubic meters. Then, add the weight of the tank to get the total mass.

2. What units should be used for calculating the mass of a tank floating in freshwater?

The units used for calculating the mass of a tank floating in freshwater should be consistent. This means that the density of freshwater should be in kilograms per cubic meter (kg/m3), the volume of the tank should be in cubic meters (m3), and the weight of the tank should be in kilograms (kg). This will ensure that the final result is in the correct unit of measurement, which is mass in kilograms (kg).

3. How does the density of freshwater affect the mass of a tank floating in freshwater?

The density of freshwater directly affects the mass of a tank floating in freshwater. This is because the mass of an object is equal to its density multiplied by its volume. Since the density of freshwater is 1000 kg/m3, a larger volume of freshwater will have a greater mass compared to a smaller volume. Therefore, the density of freshwater plays a crucial role in calculating the mass of a tank floating in it.

4. Can the mass of a tank floating in freshwater change over time?

Yes, the mass of a tank floating in freshwater can change over time. This can occur due to various factors such as evaporation, changes in temperature, or the addition or removal of water from the tank. Any changes in the density or volume of the freshwater will affect the overall mass of the tank. Therefore, it is important to recalculate the mass if any changes occur.

5. How is the mass of a tank floating in freshwater different from its weight?

The mass of a tank floating in freshwater is different from its weight. Mass is a measure of the amount of matter in an object, whereas weight is a measure of the force exerted on an object due to gravity. The mass of a tank will remain the same regardless of its location, but its weight will vary depending on the strength of gravity in that location. Therefore, when calculating the mass of a tank floating in freshwater, we are only concerned with the amount of matter present, not the force of gravity acting on it.

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