Temperature Question (answ=neg#-?)

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Homework Help Overview

The discussion revolves around a problem involving the heat transfer of a piece of iron when it is dropped into water, specifically focusing on the calculation of energy lost by the iron as it cools down. The subject area is thermodynamics, particularly the concept of specific heat capacity.

Discussion Character

  • Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the implications of a negative energy change, questioning whether it affects the interpretation of the result. There is discussion about the meaning of the negative value in the context of energy loss.

Discussion Status

Some participants have provided guidance on interpreting the negative value, suggesting it indicates energy lost. There is an ongoing exploration of whether the absolute value should be used in the final answer, with differing opinions on the interpretation of the question's phrasing.

Contextual Notes

Participants are considering the implications of the negative sign in their calculations and how it relates to the wording of the problem. There is a focus on understanding the context of energy loss rather than simply calculating a numerical answer.

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[SOLVED] Temperature Question (answ=neg#-?)

Homework Statement


A .03kg piece of iron is heated to 100 degrees celsius and then dropped into cool water where the iron's temperature drops to 30 degrees celsuis. How many joules does it lose to the water?(Specific Heat Capacity of Iron=450J)

Homework Equations


change-in-energy=(SHC)(m)(Tf-Ti)

The Attempt at a Solution



change-in-energy=(450)(.03)(30-100)
=-945J
does it matter that my answer is a negative number?
 
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You found the change in energy, which is the final energy-the initial energy

the fact that it's negative implies what? Does that seem correct?
 
grantP said:
does it matter that my answer is a negative number?
Reread the phrasing of the question. (If the change in the amount of money in your wallet after playing poker is -$5, how much did you lose?)
 
ok so i think my answer should just simply be 945J instead of -945J because the negative implies that is what i lost, and evidently is exactly what was asked in the question!
is this thinking right?
 
Correct
 

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