$7-46$ During a cold winter day, wind at $42k\frac{m}{h}$ is blowing parallel to a $6-m-$high and $10-$m$-$long wall of a house. If the air outside is at $5C$ and the surface temperature of the wall is $12C,$ determine the rate of heat loss from that wall by convection. What would your answer be if the wind velocity was deubled? Answers: $10\mathrm{.}8kw,19\mathrm{.}4kw$