Law Conservation of Energy: Starting off a solution for 11b

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SUMMARY

The discussion focuses on solving problem 11b using the Law of Conservation of Energy, specifically the equation ΔEsystem + ΔEsurroundings = 0. The user has successfully solved problem 11a, yielding a velocity of 5 m/s, and aims to apply first principles to problem 11b by incorporating ΔEsystem = ΔU + ΔEk + ΔEp and ΔU = W + Q. The challenge lies in determining the appropriate system boundary to account for friction's heat generation, which affects the energy calculations.

PREREQUISITES
  • Understanding of the Law of Conservation of Energy
  • Familiarity with kinetic energy (Ek) and potential energy (Ep)
  • Knowledge of work-energy theorem and its application
  • Basic principles of thermodynamics, specifically heat transfer (Q) and work (W)
NEXT STEPS
  • Study the implications of system boundaries in thermodynamic problems
  • Learn about the work-energy theorem and its formal derivation
  • Research the effects of friction on energy conservation in mechanical systems
  • Explore advanced applications of the Law of Conservation of Energy in various physics problems
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and thermodynamics, as well as educators seeking to clarify concepts related to energy conservation and system boundaries.

Jigga
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Homework Statement


upload_2018-6-9_17-43-24.png


Homework Equations


ΔEsystem + ΔEsurroundings =0

The Attempt at a Solution


I have solved 11a and got 5m/s.
I can do 11b just by just jumping to Ek = Fs (from the work kinetic energy theorem), but I would like to do it formally from first principles using the Law of Conservation of Energy.
I would then like to make use of
ΔEsystem + ΔEsurroundings =0
and then make use of ΔEsystem = ΔU + ΔEk + ΔEp
and then make use of ΔU = W + Q
and then introduce W = Fs
then solve for F.
However I am not sure where to put the system boundary so this is solvable. Then the question of the pluses and minuses.


Many thanks
 

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Depending on where you draw the system boundary the heat generated by friction will either remain within the system boundary (part of Delta E system) or cross the boundary (part of Delta E Surroundings) either way it's solvable.
 
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