You've experienced convection cooling if you've ever extended your hand out the window of a moving vehicle or into a flowing water stream. With the surface of your hand at a temperature of 30°C, determine the convection heat flux for

(a) A vehicle speed of 35 km/h in air at –5°C with a convection coefficient of 40 W/m² K and

(b) A velocity of 0.2 m/s in a water stream at 10°C with a convection coefficient of 900 W/m 2. K.

Which condition would feel colder? Contrast these results with a heat loss of approximately 30 W/m 2 under normal room conditions.