Pressure, Buoyant Force problem 8

In summary, the scale will read 24.4 g when the piece of metal with a density of 3.800 kg/dm^3 and volume of 2.40 cm^3 is suspended in the water. This is due to the upthrust on the metal, which is equal to the weight of water displaced, causing a downthrust on the balance.
  • #1
ChunkymonkeyI
35
0

Homework Statement


When a beaker partially filled with water is placed on an accurate scale the scale reads 22.0 g. If a piece of metal with a density of 3.800 kg/dm^3 and volume of 2.40 cm^3 is suspended by a thin string so that the metal is submerged in the water does not rest at the bottom of the beaker, what does the scale read

Homework Equations


Density=m/v
F=mg
Fb=density of fluid times volume of fluid times g
Fb=F(bottom) minus F(top)
f(apparent)=F(weight) minus Fb

The Attempt at a Solution


First I used the beaker that was partially filled with water and tried solving for the force
F=mg
F=.0022kg times 9.80 m/s^2
F=0.02156 N

Then I Solved for force again with the density and volume given but then I just realize how does that help me so idk what 2 do please help me?
 
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  • #2
the submerged piece of metal experiences an UPTHRUST equal to the weight of water displaced (2.4cm^3 is displaced) (density of water = 1gram/cm^3)
Newton's 3rd law tells you that every action(force) has a reaction(force) which is equal and in the opposite direction.
This means that the UPTHRUST must produce a 'downthrust' (my term... not a technical term)
Can you find what the balance will, read from this information?
 
  • #3
technician said:
the submerged piece of metal experiences an UPTHRUST equal to the weight of water displaced (2.4cm^3 is displaced) (density of water = 1gram/cm^3)
Newton's 3rd law tells you that every action(force) has a reaction(force) which is equal and in the opposite direction.
This means that the UPTHRUST must produce a 'downthrust' (my term... not a technical term)
Can you find what the balance will, read from this information?

If I multiply the density of water by the volume of the object (1000 kg/m^3 times 2.4 times 10^-6) then I get a mass of 0.0024 kg and Ik the answer has to be 24.4 g so Idk what I am doing wrong
 
  • #4
You have done it! 0.0024Kg is 2.4g. This is the Upthrust on the piece of metal and therefore the downthrust on the balance so the reading increases by 2.4g to give a reading of 24.4g
 
  • #5
Wow omg thanks :)
 

Related to Pressure, Buoyant Force problem 8

1. What is pressure?

Pressure is the force exerted per unit area. It is typically measured in units of pascals (Pa) or newtons per square meter (N/m^2).

2. How is pressure related to buoyant force?

Pressure is a key factor in determining the buoyant force acting on an object. The greater the pressure exerted by a fluid on the surface of an object, the greater the buoyant force pushing upwards on that object.

3. What is the formula for calculating pressure?

The formula for pressure is pressure = force / area. In the context of buoyant force, the force is the weight of the fluid above the object and the area is the surface area of the object in contact with the fluid.

4. How does the density of the fluid affect the buoyant force?

The density of the fluid plays a significant role in determining the buoyant force. A denser fluid will exert more pressure and therefore result in a greater buoyant force. This is why objects will float higher in denser fluids such as saltwater compared to freshwater.

5. Can you explain Archimedes' principle and how it relates to buoyant force?

Archimedes' principle states that the buoyant force on an object immersed in a fluid is equal to the weight of the fluid that the object displaces. This means that the buoyant force acting on an object is equal to the weight of the fluid that would occupy the space that the object is occupying. This principle is key in understanding the relationship between pressure and buoyant force.

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