Question

1. [3 marks] For someone of mass 85 kg, how much energy is needed to increase their temperature from T₀ = 37.0 °C to 38.4 °C?
2. [5 marks] The forehead is well known to be a body location that indicates the internal body temperature. For this person, the forehead is at the internal body temperature of 38.3°C, and the tip of nose remains at the room temperature of 25°C. Given that the emissivity of the body is 0.8, how many times more is the radiative intensity (Wm^-2) of the forehead compared to the nose?
3. [5 marks] What is the net radiative intensity (in Wm^-2) of the forehead?
4. [7 marks] The metabolic energy generated in the person is 3.5´10⁶ J in a 6 hour period, and this is balanced by cooling of the body by 2.6 L of perspiration and radiative cooling (you can neglect conductive and convection cooling). What is the effective surface area of the person?

Answer 1

ud Week 17th Day The the net la diartinse intew ally of forehea al is, - 6.0(311.374 won2 Cas done before) - 0.8x. 5 6 7 x 18 8 x (3113) wenn = 0.0425 won 2. MAR APR MAY

ud Week 17th Day The the net la diartinse intew ally of forehea al is, - 6.0(311.374 won2 Cas done before) - 0.8x. 5 6 7 x 18 8 x (3113) wenn = 0.0425 won 2. MAR APR MAY

a. , доу (1) e &и initial temperature = 2700 (to фіри ( 1) 2. 20:"L { €, The average specific heat of human bоdу us (5) 3:6 417 4- We hoy boat energy needed to in brease the temperature is, 9 см 546 2 4 ( t = 61). с (85) (3-4) (370) 2 42e: 14 ) . E42g4 00 ) од .

bir We know, - the energy radiated per unit tume by a surface area A is; Ez eSATU. where l = emissivitly = 0.8 (given) or doltaman 6 a Štefan - bourman constant of -2-4 = 5.67 x 10 8 own te TI temperature in absolute Slace (in K) Again, the ralliative intensity is Sunday 15 defined by energy radiated per unit time, per unit area. to le, Moreliative intensitty is, E eople .

11.00 1.00 2.00 3.00 radiative intensibly od 1200 of the forehead s=00(38.3 + 272) Wom 4 I er (3113) I Won 2 Alaio, and of the nouse is a eo (254 272) Wn2 - log130077 um 2 Hence, their ratio is , e 0 (311.3) 4 e0 (300) 4 4.00 5.00 6.00 7.00 - (311.3.19 300 I 1.159395 ~ 1.16 so ralliative emissivity of forehead is de almout 1.16 times more than the nose.