On a cool day in April a scantily clothed runner is known to lose heat at a rate of 500 W because of convection to the surrounding air at T. 10。C. The runner's skin remains dry and at a temperature of Ts = 300C. Three months later, the runner is moving at the same speed, but the day is warm and humid with a temperature of T.-30°C and a relative humidity of g'-=7096. The runner is now drenched in sweat and has a uniform surface temperature of 350C. Under both conditions constant air properties may be assumed with v1.6 x 10-5 m2/s, k 0.026 W/m-K, Pr 0.70, and DAB (water vapor-air) -2.3 x 105 m2/s.

(a) What is the rate of water loss, in kg/s, due to evaporation on the summer day? kg/s

(b) What is the total convective heat loss, in w, on the summer day?