In very cold weather, a significant mechanism for heat loss by the human body is the energy expended in warming the air taken into the lungs with each breath. (a) On a cold winter day when the temperature is - 20 ℃, what amount of heat is needed to warm body temperature (37 ℃) the 0.60 L of air exchanged with each breath? Assume that the specific heat of air is 1020 J/kg.K and that 1.0 L of air has a mass of 1.3 x 10-3 kg. (b) How much heat is lost per hour if the respiration rate is 20 breaths per minute?

In very cold weather, a significant mechanism for heat loss by the human body is the energy expended in warming the air taken into the lungs with each breath. (a) On a cold winter day when the temperature is - 20 ℃, what amount of heat is needed to warm body temperature (37 ℃) the 0.60 L of air exchanged with each breath? Assume that the specific heat of air is 1020 J/kg.K and that 1.0 L of air has a mass of 1.3 x 10-3 kg. (b) How much heat is lost per hour if the respiration rate is 20 breaths per minute?

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