Multiple-Concept Example 8 reviews the approach that is used inproblems such as

Question

Multiple-Concept Example 8 reviews the approach that is used inproblems such as this. A person eats a dessert that contains 230Calories. (This "Calorie" unit, with a capital C, is the one usedby nutritionists; 1 Calorie = 4186 J. See Section 12.7.) The skintemperature of the person is 36.8 °C and that of herenvironment is 16.2 °C. The emissivity of her skin is 0.82 andits surface area is 1.0 m2. How many hours would it takeher to emit a net radiant energy from her body that isequal to the energy contained in this dessert?

Number

Units

The number of significant digits is set to 3; the toleranceis +/-2%

Chapter 13, Problem 29

Explanation / Answer

      P = Ae (T4 -T04 )       = (1.2m2 ) (0.740(5.67*10-8 ) (309.84 -289.24 )       = 111.6 J/s we know that power P = Q/t so time t = Q/P = (230) (4.186J ) / 111.6 J/s =8.62s

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.