A runner moves along the road at 2.0 `ms^(1)` in still air that is at a temperature of `29.0^(0)`C. His surface area is 1.4 `m^(2)`, of which approximately 85% is exposed to the air. Find the rate of convective heat loss from his skin at a temperature `35.0^(0)` C to the outside air? Coefficient of convection for dry air and bare skin at wind speed `2.0 ms^(-1)`' is 22 W/m2`""^(@)` C .

Explanation

From Eq. `(Q)/(t) = lambda A Delta T ` Given `lambda ` = Coefficient of conduction
` = 22 W // m^(2 0) C, Delta T = 35.0^(@)C - 29.0^(@)C = 6.0^(@)C`
A =85% of the surface area of the runner `1.4m^(2) = 1.2 m^(2)`
Upon substituting the value `(Q)/(t) = 22W // m^(20)C xx 1.2 m^(2) xx 6.0^(@)C = 160 W `