In very cold weather a significant mechanism for heat loss by the human body is

Question

In very cold weather a significant mechanism for heat loss by the human body is energy expended in warming the air taken into the lungs with each breath.

Part A

On a cold winter day when the temperature is 20C, what amount of heat is needed to warm to body temperature (37 C) the 0.50 L of air exchanged with each breath? Assume that the specific heat of air is 1020 J/kgK and that 1.0 L of air has mass  1.3×103kg.

Express your answer using two significant figures.

SubmitMy AnswersGive Up

Part B

How much heat is lost per hour if the respiration rate is 20 breaths per minute?

Express your answer using two significant figures.

SubmitMy AnswersGive Up

In very cold weather a significant mechanism for heat loss by the human body is energy expended in warming the air taken into the lungs with each breath.

Part A

On a cold winter day when the temperature is 20C, what amount of heat is needed to warm to body temperature (37 C) the 0.50 L of air exchanged with each breath? Assume that the specific heat of air is 1020 J/kgK and that 1.0 L of air has mass  1.3×103kg.

Express your answer using two significant figures.

Q =   J  

SubmitMy AnswersGive Up

Part B

How much heat is lost per hour if the respiration rate is 20 breaths per minute?

Express your answer using two significant figures.

Qt =   J/hour  

SubmitMy AnswersGive Up

Explanation / Answer

temperature is 20C,

body temperature (37 C) the 0.50 L

specific heat of air is 1020 J/kgK

1.0 L of air has mass  1.3×103kg.

20 breaths per minute

a) (1020 [J/(kg•K)])(0.5 L)(1.3·10³ kg/L)(37-20 K) = 37.39 J.

b) (37.39 J/breath)(20 breaths/min)(60 min/hr) = 4.53·10 J/hr

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

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