Converting Newton's Law of Cooling from Heat Loss to Temperature Decay

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SUMMARY

The discussion focuses on converting Newton's Law of Cooling, represented by the equation dQ/dt = k (T - Troom), into a form that expresses the rate of temperature decay, dT/dt. The participant attempts to manipulate the equation but struggles with the relationship between heat loss (Q) and temperature (T). They derive an expression involving T(t) and Q(t) but realize that without knowing T(t), direct computation of dT/dt is not feasible. The key takeaway is that a clear understanding of the relationship between heat loss and temperature is essential for this conversion.

PREREQUISITES
  • Understanding of differential equations
  • Familiarity with Newton's Law of Cooling
  • Knowledge of heat transfer concepts
  • Basic calculus skills
NEXT STEPS
  • Study the derivation of Newton's Law of Cooling in detail
  • Learn about solving first-order differential equations
  • Explore the relationship between heat loss and temperature decay
  • Investigate applications of temperature decay in real-world scenarios
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Students studying thermodynamics, physics enthusiasts, and anyone interested in the mathematical modeling of heat transfer processes.

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Homework Statement


The equation dQ/dt = k ( T - Troom) is Newtons law of cooling. dQ/dT being the rate of heat loss. I want to convert this equation to dT/dt, the rate of temperature decay. How do i go about doing this?


Homework Equations





The Attempt at a Solution



Is Q proportional to T? then i can just sub it in for Q and solve for the differential equation?
 
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Well, Q is not proportional to T. Here's what I did:

\frac{dQ(t)}{dt} = k(T(t)-T_0)

\frac{1}{k}\frac{dQ(t)}{dt} +T_0 = T(t)

\frac{d}{dt}T(t) = \frac{1}{k}\frac{d^2Q(t)}{dt^2}
 
To me, it seems like you need T(t) to solve for Q(t). But if you already had T(t), then you could just get T'(t) by direct computation. You don't have it though...
 

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