How to define kinetic energy of a compound system

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SUMMARY

The discussion focuses on defining the total kinetic energy of a compound system, specifically an Atwood machine consisting of two connected masses. The key equation referenced is ΔK + ΔU = 0, indicating the relationship between changes in kinetic and potential energy in an isolated system. The participants clarify that for connected masses, the final kinetic energy can be treated as a single entity, while for non-connected masses, the total kinetic energy is simply the sum of the individual kinetic energies of each mass.

PREREQUISITES
  • Understanding of kinetic energy and potential energy concepts
  • Familiarity with the Atwood machine mechanics
  • Knowledge of isolated systems in physics
  • Basic algebra for summing energies
NEXT STEPS
  • Study the principles of energy conservation in isolated systems
  • Learn about the dynamics of the Atwood machine in detail
  • Explore the concept of kinetic energy for multiple objects in motion
  • Investigate the differences between connected and non-connected mass systems
USEFUL FOR

Students of physics, educators teaching mechanics, and anyone interested in understanding energy dynamics in systems with multiple moving parts.

Davyd Sadovskyy
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A system is defined as two connected masses in an atwood machine and the earth. How do I find total kinetic energy in a system where more than one object is moving (or is only one object actually moving since the two masses are connected with a string? idk)
upload_2017-11-3_21-30-10-png.png


This is an isolated system so... ΔK + ΔU = 0

How do I define energies of a system if there are multiple moving parts, each with its own energy? This is at the core of my confusion. I know that initially, there are no particles in this system with velocity, so Ki must be 0.
These are my questions

1.) How would you define the final kinetic energy? Do you treat the two moving blocks as a singly block instead of 2 separate blocks?

2.) What if a system consisted of 2 non connected blocks. How would you define final kinetic energy then?
 

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Davyd Sadovskyy said:
How do I define energies of a system if there are multiple moving parts, each with its own energy?
Just add them together.

Davyd Sadovskyy said:
What if a system consisted of 2 non connected blocks. How would you define final kinetic energy then?
Just add them together.
 

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