Rate will this student burn calories

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SUMMARY

The discussion centers on calculating the rate at which a student will burn calories while sitting naked in a 12.5° C room. The student uses the equation dQ/dt=h.A.dT, where h is the heat transfer coefficient, A is the surface area (1.7 m²), and dT is the temperature difference. The initial calculation yielded 502.35 J/s, but the student questioned the accuracy of the temperature used, specifically whether it should be 288.5 K or 285.5 K. The correct temperature difference is crucial for accurate calorie burn calculations.

PREREQUISITES
  • Understanding of thermodynamics principles, specifically heat transfer.
  • Familiarity with the concept of emissivity in thermal radiation.
  • Knowledge of basic calculus for rate of change calculations.
  • Ability to convert between energy units (Joules to kilocalories).
NEXT STEPS
  • Review the principles of thermal radiation and emissivity.
  • Learn how to accurately apply the heat transfer equation dQ/dt=h.A.dT.
  • Study the conversion of Joules to kilocalories for practical applications.
  • Explore the effects of environmental temperature on metabolic rate calculations.
USEFUL FOR

Students in physics or engineering, fitness enthusiasts calculating caloric burn, and anyone interested in thermodynamics and heat transfer principles.

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rate will this student "burn" calories

Homework Statement


A student wants to lose some weight. He knows that rigorous aerobic activity uses about 700 kcal/h (2900 kJ/h) and that it takes about 2000 kcal per day (8400 kJ) just to support necessary biological functions, including keeping the body warm. He decides to burn calories faster simply by sitting naked in a 12.5° C room and letting his body radiate calories away. His body has a surface area of about 1.7 m2 and his skin temperature is 35° C. Assuming an emissivity of 1.0, at what rate will this student "burn" calories?


Homework Equations


dQ/dt=h.A.dT
1*1.7*295.5
=502.35 J/s

Why is my answer wrong?
 
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Is T not 288.5K ?
 


marcoskids said:
Is T not 288.5K ?

Sorry 285.5K
 


Yes your right but even with that I still get the wrong answer
 

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