Chapter 1, Problem 1.18P

You’ve experienced convection cooling if you’ve everextended your hand out the window of a moving vehicle or into a flowing water stream. With the surface ofyour hand al a temperature of 30°C, determine the convection heal flux for (a) a vehicle speed of 35 km/h inair at $-5°\text{C}$ with a convection coefficient of $40{\text{W/m}}^2\cdot \text{K}$ and (b) a velocity of 0.2 m/s in a water streamat 10°C with a convection coefficient of $\text{900}{\text{W/m}}^2$ .Which condition would feel colder? Contrast these results with a heat loss of approximately $\text{30}{\text{W/m}}^2$ under normal room conditions.