Question

The normal body-temperature of a person is ${97}^{\circ }F$ Calculate the rate at which heat is flowing out of his body through the clothes assuming the following values. Room temperature = ${47}^{\circ }F$, surface of the body under clothes = $1.6m^2$, conductivity of the cloth = $0.04J{s}^{-1}{m}^{-1\circ }{C}^{-1}$, thickness of the cloth = 0.5 cm.

Answer 1

K = $0.04J/m-S^{\circ }C$,

A= 1.6 $m^2$

$T_1={97}^{\circ }F={36.10}^{\circ }C$

$T_2={47}^{\circ }F={8.330}^{\circ }C$

l = 0.5 cm = 0.005 m

$\frac{Q}{t}=\frac{KA({\theta }_1-{\theta }_2)}{l}$

= $\frac{0.04\times 1.6\times \left(27.7\right)}{0.005}=356J/s$