# Finding the density of a liquid with buoyancy

• bearhug
In summary, the conversation discusses the use of the equation B=p(fluid)ghA to determine the density of a liquid in units of g/cm^3. The graph provided shows the apparent weight of a rectangular block as it is submerged into the liquid. The equation shows the relationship between the apparent weight and the buoyant force, which is equal to the area of the face times the pressure. The conversation also discusses the connection between the slope of the graph and the constant factors in the equation.

#### bearhug

http://spock.physast.uga.edu/prtspool/bearhug_uga_printout_1163471689_22380_10.pdf
A rectangular block is gradually pushed faced-down into a liquid. The block has height d; on the bottom and top the face area is A=5.67 cm^2 . Also shown is a graph that shows the apparent weight W_app of the block as a function of the depth h of its lower face. What is the density of the liquid in units of g/cm^3

Originally I used the equation B=p(fluid)ghA and solved for the density of the fluid. First of all, is this the right equation to use?

I can't for some reason post the figures but if anyone can still give me some help without the use of the figures would be greatly appreciated.

Apparent weight W_a is actual weight W minus the buoyant force B.

W_a = W - B

I assume your graph starts with W_a = 0 at some h and then goes down as h increases. The buoyant force is the Area of the face times the pressure (ρgh), as you have written it. Everything in B is a constant except for h, and W is a constant. The equation above is the equation of a straight line. There is a connection between the slope of that line and the constant factors in B. What is that connection?

## 1. What is the definition of buoyancy?

Buoyancy is the upward force that a fluid exerts on an object that is immersed in it. This force is equal to the weight of the fluid that is displaced by the object.

## 2. How do you find the density of a liquid using buoyancy?

To find the density of a liquid using buoyancy, you need to measure the weight of the object in air and then in the liquid. The difference in weight is equal to the weight of the displaced liquid. Then, you can use the formula density = mass/volume to calculate the density of the liquid.

## 3. What is the principle behind using buoyancy to find density?

The principle is based on Archimedes' principle, which states that the buoyant force acting on an object is equal to the weight of the fluid it displaces. By measuring the buoyant force, we can determine the weight of the displaced fluid and use it to calculate the density of the liquid.

## 4. What tools are needed to find the density of a liquid with buoyancy?

The tools needed include a scale to measure the weight of the object, a container to hold the liquid, and a ruler or caliper to measure the volume of the object. You may also need a calculator to perform the necessary calculations.

## 5. Are there any factors that can affect the accuracy of the density measurement using buoyancy?

Yes, there are a few factors that can affect the accuracy of the measurement. These include the accuracy of the measurements taken, the shape and size of the object, and the temperature of the liquid. It is important to take multiple measurements and average them to improve the accuracy of the result.