A5-mm-thick stainless steel strip (k = 21 w/m•k, rho = 8000 kg/m3, and cp = 570 j/kg•k) is being heat treated as it moves through a furnace at a speed of 1 cm/s. the air temperature in the furnace is maintained at 1020°c with a convection heat transfer coefficient of 80 w/m2•k. if the furnace length is 3 m and the stainless steel strip enters it at 20°c, determine the temperature of the strip as it exits the furnace.

Explanation:

we know that biot number is given as

where Lc is characteristics length

as biot number is less than 0.1 thus apply lumper analysis to find time constant t

considerig temperature distiribution

temperature at mid length of furnase is

T(t) = 592.885 degree c

from Newton's law of cooling determine temp gradient at surface at t = 150 s

answer; equivalent to a one(1) horsepower motor;

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table