Qualitative physics question

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In summary, the question asks if the reading on the scale will increase, decrease, or stay the same when a metal ball is lowered into a beaker of water using a string. The answer to this question depends on the buoyant force, which is the force exerted by the water on the object. Even if the metal ball is the same density as the water, there will still be a buoyant force. If the ball sinks, it will displace some water, leading to a difference in the weight of the ball underwater. Therefore, the reading on the scale will change when the ball is introduced into the beaker of water.
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Homework Statement



A beaker of water rests on a scale. A metal ball is then lowered into the beaker using a string tied to the ball. The ball doesn't touch the sides or bottom of the beaker, and no water spills from the beaker.

Does the reading on the scale increase, decrease, or stay the same?

Homework Equations





The Attempt at a Solution



I think it increases, cause your introducing an object ontop of the water and u are therefore chaning the mass of the water

AM I wrong?
 
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  • #3
Nellen2222 said:
I think it increases, cause your introducing an object ontop of the water and u are therefore chaning the mass of the water

AM I wrong?
Why would the mass of the water change? What does change about the water?
 
  • #4
is the object just touches the water and is ontop then I don't know, i guess there is no bouyant force, just the ball displaces some fluid from the top but since displaced fluid = to the mass it makes no difference, is that right?
 
  • #5
Sure there's buoyant force. Have you ever held a rock or something heavy under water? Although it sinks, it still appears lighter. Whenever an object displaces water, there will be a buoyant force on the object. If the metal ball sinks, it's denser than the water, and the mass of displaced fluid will not equal the mass of the ball. Even if the metal ball were the same density, as the water, there would be a buoyant force.

For example, if the ball weighs 5N, and when it sinks, it displaces 2N of water, the weight of the ball would be 5N-2N=3N underwater. 2N is the buoyant force.

The answer to this question very much has to do with this buoyant force.
 
Last edited:

1. What is qualitative physics?

Qualitative physics is the study of physical phenomena and their behaviors without the use of numerical or mathematical equations. This approach focuses on understanding the concepts and principles behind physical systems and their interactions, rather than solely on quantitative analysis.

2. How is qualitative physics different from quantitative physics?

Quantitative physics involves using mathematical equations and measurements to explain and predict the behavior of physical systems. Qualitative physics, on the other hand, focuses on understanding the underlying principles and relationships between different physical phenomena without the use of numbers or equations.

3. What are some examples of qualitative physics questions?

Examples of qualitative physics questions include: How does the force of gravity affect the motion of objects? What causes objects to have different densities? How do different materials conduct electricity? These questions focus on understanding the principles and relationships between physical phenomena, rather than just calculating specific values.

4. How is qualitative physics used in scientific research?

Qualitative physics is used in scientific research to gain a deeper understanding of physical systems and phenomena. It can help scientists formulate hypotheses, design experiments, and interpret results. It is also commonly used in fields such as engineering and environmental science to analyze and predict the behavior of complex systems.

5. What are the limitations of qualitative physics?

One limitation of qualitative physics is that it cannot provide precise numerical predictions or solutions. This can make it difficult to apply in certain situations, such as designing structures or creating precise models. Additionally, qualitative physics may not be suitable for all types of physical systems, as some may require more quantitative analysis to fully understand their behavior.

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