This question concerns a $1$ cm outside diameter horizontal hot water pipe as it passes through a space whose air temperature is $5$oC$.$ The outer surface temperature of the pipe is $75$oC$.$ The length of the pipe is $3$ m$.$ Neglect thermal radiation.

a$)$

Determine the heat loss $($in W$)$ as a consequence of natural convection.

Unanswered

b$)$

Determine the heat loss $($in W$),$ as a consequence of a cross flow. The air velocity is $11$ m$/$s$.$