Newton's law of cooling question, no inital temperature given

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SUMMARY

The discussion centers on applying Newton's Law of Cooling to determine the initial temperature of an object that cooled from 31°C to 30°C over one hour in a room at 20°C. The relevant equation is dT/dt = k (T - Ts), where Ts is the ambient temperature. The solution approach involves recognizing that the initial temperature can be assumed as 31°C at time t=0, simplifying the problem. The key takeaway is that the time spent before the first measurement does not affect the calculation of the initial temperature.

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miniradman
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Homework Statement


The temperature of an object has been lying at rest and cooling for sometime had been found to be 31oC. An hour later, the same object was found to be 30oC. The room was also What was the initial temperature of the object, assume Newton's law of cooling applies.


Homework Equations


Newton's law of cooling

\frac{dT}{dt} = k (T - Ts) where:

Ts = ambient temperature
T = the temperature at anytime
k = constant of proportionality


The Attempt at a Solution


Ok, normally when I do a Newtons law of cooling question, I start off with the inital temperature followed by a temperature at an "X" time. And then I would convert the formula into it's exponential form i.e. y = Aekt+c. then I would use the initial temperature (or the temperature when t=) to cancel out one of the variables. However, I'm trying to find the inital temperature, so this method won't work for me anylonger and I'm not sure how to proceede :confused:

Thanks guys/gals, any help will be greatly appreciated :biggrin:
 
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miniradman said:

Homework Statement


The temperature of an object has been lying at rest and cooling for sometime had been found to be 31oC. An hour later, the same object was found to be 30oC. The room was also What was the initial temperature of the object, assume Newton's law of cooling applies.
"The room was also" - what? Where's the rest of this sentence?
miniradman said:

Homework Equations


Newton's law of cooling

\frac{dT}{dt} = k (T - Ts) where:

Ts = ambient temperature
T = the temperature at anytime
k = constant of proportionality

The Attempt at a Solution


Ok, normally when I do a Newtons law of cooling question, I start off with the inital temperature followed by a temperature at an "X" time. And then I would convert the formula into it's exponential form i.e. y = Aekt+c. then I would use the initial temperature (or the temperature when t=) to cancel out one of the variables. However, I'm trying to find the inital temperature, so this method won't work for me anylonger and I'm not sure how to proceede :confused:

Thanks guys/gals, any help will be greatly appreciated :biggrin:
 
Sorry, the room was also found to be 20 degrees celsius
 
Take the initial temperature to be 31°C at t=0. The time spent lying at rest in the room doesn't matter before the temp was measured.
 

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