Ex$3$

A$50-$m$-$long section of a steam pipe whose outer diameter is $10$ cm passes through an open space at $15C.$ The average temperature of the outer surface of the pipe is measured to be $150C.$ If the combined heat transfer coefficient on the outer surface of the pipe is $20\frac{W}{m}2*C,$ determine the rate of heat loss from the steam pipe. and $($c$)$ the thickness of fiberglass insulation $\frac{W}{m}*C)$ needed in order to save $90$ percent of the heat lost. Assume the pipe temperature to remain constant at $150C.$