"Isolated system model" can someone explain this to me?

In summary, the objects in this problem are treated separately because their energies and heights are different, making it easier to calculate their velocities and heights.
  • #1
doneky
13
0

Homework Statement


Two objects are connected by a light string passing over a light, frictionless pulley as shown in the figure below. The object of mass m1 = 4.80 kg is released from rest at a height h = 4.40 m above the table.
8-p-007.gif

(a) Using the isolated system model, determine the speed of the object of mass m2 = 3.00 kg just as the 4.80–kg object hits the table.
(b) Find the maximum height above the table to which the 3.00–kg object rises.

Homework Equations


KE = 1/2*mv^2
PE = mgh

The Attempt at a Solution


So, basically the answer is to combine the total changes in kinetic and potential energy, where nonconservative work equals zero.

But why? Why should these be treated separately instead of using a combined mass?
 
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  • #2
doneky said:
But why? Why should these be treated separately instead of using a combined mass?
I do not understand your question. You are to consider the combined energies, no? That effectively combines the masses.
An approach that does not directly combine the masses is to work in terms of forces, treating each mass separately. They become connected then by using common values for tension and acceleration.
 
  • #3
The reason they are being treated as separate bodies is because the energy for each object is different from the other. If you were to treat both object as same, it would be very difficult to calculate the velocity of the connected bodies, because the velocity of m1 is different from m2. Same is the case is for GPE. The height from the reference point is different for both objects.
 

1. What is an isolated system model?

An isolated system model is a theoretical framework used in scientific experiments to study the behavior of a specific system without any external influences. This means that the system is completely closed off from its surroundings and does not exchange matter or energy with its environment.

2. How does an isolated system model differ from an open system model?

An open system model allows for the exchange of matter and/or energy with its surroundings, while an isolated system model does not. This makes the isolated system more controlled and easier to study, as there are no external factors influencing the system.

3. What are the advantages of using an isolated system model in scientific experiments?

The use of an isolated system model allows for more precise and controlled experiments, as external factors are eliminated. This can lead to more accurate results and better understanding of the behavior of the system being studied.

4. Can an isolated system ever truly exist in nature?

It is unlikely that an isolated system can exist in nature, as all systems are influenced by their surroundings to some degree. However, the concept of an isolated system is useful for theoretical and experimental purposes in scientific research.

5. How is the concept of an isolated system model applied in different fields of science?

The isolated system model is used in various fields of science, including physics, chemistry, and biology. In physics, it is used to study the behavior of thermodynamic systems. In chemistry, it is used to study chemical reactions in controlled environments. In biology, it is used to study the behavior of living organisms in controlled conditions.

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