# Confusion about the difference between isolated and non isolated systems

• eduardogallegos9
In summary: If there are other forces at play, then the answer would be something like "The system is not isolated if there are other forces at play that influence the motion."
eduardogallegos9
Homework Statement
A child of mass m starts from rest and slides without friction from a height h along a slide next to a pool (Fig. P8.13).
She is launched from a height h/5 into the air over the pool.
We wish to find the maximum height she reaches above the
water in her projectile motion. (a) Is the child–Earth system
isolated or nonisolated? Why?
Relevant Equations
n/a
Read the book and conducted research on the internet. Came to conclusion that this was an isolated system because the girl was being accelerated by gravity but answer is non isolated. Can someone please help me grasp this concept better.

eduardogallegos9 said:
Homework Statement:: A child of mass m starts from rest and slides without friction from a height h along a slide next to a pool (Fig. P8.13).
She is launched from a height h/5 into the air over the pool.
We wish to find the maximum height she reaches above the
water in her projectile motion. (a) Is the child–Earth system
isolated or nonisolated? Why?
.
..Came to conclusion that this was an isolated system because the girl was being accelerated by gravity but answer is non isolated.
I agree with you - isolated. The only force doing work is the gravitational attraction between the Earth and the girl. The earth-girl system has constant internal mechanical energy (kinetic + potential), so there is no energy-transfer to/from the system.

(Note, with a wider view, the earth-girl system is not closed. E.g. the Earth receives light energy from the sun; this is incorporated into food. This energy then enables the girl to climb up the slide in the first place! But, in the context of the question, this seems an inappropriate interpretation of 'isolated'.)

Edited - typo'.

eduardogallegos9
eduardogallegos9 said:
Homework Statement:: A child of mass m starts from rest and slides without friction from a height h along a slide next to a pool (Fig. P8.13).
She is launched from a height h/5 into the air over the pool.
We wish to find the maximum height she reaches above the
water in her projectile motion. (a) Is the child–Earth system
isolated or nonisolated? Why?
Relevant Equations:: n/a

Read the book and conducted research on the internet. Came to conclusion that this was an isolated system because the girl was being accelerated by gravity but answer is non isolated. Can someone please help me grasp this concept better.
If the system is not isolated, then what else must be brought into the equation? What else influences the motion in this case? If the answer is nothing, then you have an isolated system.

eduardogallegos9

## 1. What is the main difference between isolated and non-isolated systems?

The main difference between isolated and non-isolated systems is the exchange of matter and energy with the surroundings. Isolated systems do not allow any exchange, while non-isolated systems can exchange matter, energy, or both.

## 2. How can I identify if a system is isolated or non-isolated?

You can identify if a system is isolated or non-isolated by looking at the boundaries of the system and observing if there is any exchange of matter or energy with the surroundings. If there is no exchange, the system is isolated, and if there is exchange, it is non-isolated.

## 3. Can a system be both isolated and non-isolated?

No, a system cannot be both isolated and non-isolated at the same time. It is either one or the other, depending on the exchange of matter and energy with the surroundings.

## 4. What are some examples of isolated and non-isolated systems?

An example of an isolated system is a thermos, where there is no exchange of matter or energy with the surroundings. An example of a non-isolated system is a pot of boiling water, where there is an exchange of energy with the surroundings in the form of heat.

## 5. Why is it important to understand the difference between isolated and non-isolated systems?

Understanding the difference between isolated and non-isolated systems is crucial in many scientific fields, such as thermodynamics and chemistry. It allows us to accurately describe and predict the behavior of systems and their surroundings, which is essential in many practical applications.

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