Fluid Physics; Finding the Density of an Unknown Liquid

In summary, the conversation discusses a problem from the 2002 AP exam which involves finding the density of an unknown liquid. The person is trying to solve for the unknown density by assuming that the object is submerged in the liquid and disperses a volume of water equal to its own volume. They are also trying to understand the concept of buoyant force and how it relates to the weight of the object and the weight of the unknown liquid's volume. The conversation also mentions using the known density of mass to find the volume and the relationship between force and buoyant force.
  • #1
Jinthe1st
2
0

Homework Statement


I have a problem from the 2002 AP exam; The questions specifically are from 3b, c, and d. ( See the attached image.)

Homework Equations


So I'm trying to solve for the unknown density of the liquid (pW). From what I can assume so far, the object is submerged in the liquid, dispersing a volume of water equal to the volume of the object; however, I suppose there will be a different dimension? I believe that the height determined from the object to the surface of the liquid will be essential to this problem?

I believe I am trying to find the weight of the unknown liquid's volume. Would that be the same as the weight of the object?

I think I do not understand some of the concepts at hand, honestly.

The Attempt at a Solution


F=kx
F=Weight
Weight (N)= Fb (Buyant Force)

Density of mass is known; use that to find the volume:
Weight = (Density)(volume)(Gravity acceleration)
W= (p)(v)(g)

Volume of object = Volume of liquid
Fb = pL(v)(g)
 

Attachments

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  • #2
What will happen to the stretch of the spring when you dunk the mass into the fluid? Assuming that you found the spring constant in part a, what can you deduce?
 
  • #3
Ah, the force should be reduced somewhat; will that be the the buoyant force?
 
  • #4
Jinthe1st said:
Ah, the force should be reduced somewhat; will that be the the buoyant force?
The change in spring force will tell you the buoyant force. (Draw yourself a free body diagram for the object.)
 

1. What is fluid physics?

Fluid physics is the study of the behavior of fluids, which includes liquids and gases, and how they interact with their surroundings. It is a branch of physics that focuses on the properties and dynamics of fluids.

2. Why is it important to find the density of an unknown liquid?

Density is an important physical property of a substance that helps in identifying and characterizing it. It can also provide information about the purity and composition of a substance. Therefore, finding the density of an unknown liquid is essential for various scientific and industrial applications.

3. How do you find the density of an unknown liquid?

The density of a substance is calculated by dividing its mass by its volume. To find the density of an unknown liquid, you would need to measure its mass using a scale and its volume using a graduated cylinder or a volumetric flask. Then, you can simply divide the mass by the volume to determine the density.

4. What factors can affect the accuracy of the density measurement?

There are several factors that can affect the accuracy of the density measurement of an unknown liquid. These include temperature, pressure, and impurities in the liquid. It is important to control these factors as much as possible to obtain an accurate density measurement.

5. Can the density of a liquid change?

Yes, the density of a liquid can change under different conditions. For example, the density of a liquid can increase with decreasing temperature, as the particles become more closely packed. Additionally, the addition of impurities can also affect the density of a liquid. However, the density of a pure substance at a given temperature and pressure is considered a constant value.

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