Transfer of Heat: Temperature in Kelvins

  • Thread starter Thread starter MKM
  • Start date Start date
  • Tags Tags
    Heat Temperature
AI Thread Summary
A person's body generates energy through metabolic processes, and if energy loss exceeds this production, body temperature can drop dangerously. In the scenario presented, the body loses energy through radiation from a surface area of 1.24 m² at a temperature of 34 °C with an emissivity of 0.614. The metabolic energy production rate is 98.8 J/s, and the discussion involves calculating the coldest room temperature in Kelvin where the individual would not experience a temperature drop. The Stefan-Boltzmann law is referenced to analyze radiative heat transfer, indicating the need to consider both the body and room temperatures in the calculations. Accurate application of these principles is crucial for determining safe environmental conditions for the individual.
MKM
Messages
16
Reaction score
0
A person's body is producing energy internally due to metabolic processes. If the body loses more energy than metabolic processes are generating, its temperature will drop. If the drop is severe, it can be life-threatening. Suppose a person is unclothed and energy is being lost via radiation from a body surface area of 1.24 m2, which has a temperature of 34 °C and an emissivity of 0.614. Suppose that metabolic processes are producing energy at a rate of 98.8 J/s. What is the temperature in Kelvin of the coldest room in which this person could stand and not experience a drop in body temperature?


I used the formula Q= e*sigma*(T kelvins ^4) times(area) I get 384.21 after changing the temperature to 307.15 Kelvins. I am not sure where to place the rate of energy within this problem.
 
Physics news on Phys.org
The Stefan-Boltzmann law is based on the radiative heat transfer between hot and cold - i.e. (TH4 - TC4).
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Power Radiated From a Copper Cube
Replies
3
Views
796
When to convert units of temperature?
Replies
2
Views
2K
Rate body temperature increases given rate of heat transfer?
Replies
1
Views
7K
Heat Transfer: Finding temperature at the junction
Replies
3
Views
3K
Black Body Radiation and ambient temperature
Replies
7
Views
4K
Calculating thickness of insulation, rate of T rise and fall
Replies
6
Views
2K
Problem involving the human body and rate of heat transfer
Replies
6
Views
10K
I Why does the core collapse happen so fast in a supernova?
Replies
3
Views
3K
How much water is converted to ice?
Replies
1
Views
3K
Heat transfer from body through layers, using h, T, d, A
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top