5.15 Carbon steel (AISI 1010) shafts of 0.1-m diameter are heat treated in a gas-fired furnace whose gases are at 1200 K and provide a convection coefficient of 100 W/m2 -K. If the shafts enter the furnace at 300 K, how long must they remain in the furnace to achieve a centerline temperature of 800 K?

The time required to reach the center line temperature of 800 K is t = 58 sec

Explanation:

Given data

D = 0.1 m

h = 100

Specific heat for carbon steel (C) = 502.4

Furnace temperature = 1200 K

Final temperature T = 800 K

Initial  temperature = 300 K

From lumped heat analysis

 ------- (1)

Now from equation (1)

㏑ 0.44 =  -(0.001415 ) t

-(0.001415 ) t = - 0.82

t = 58 sec

Thus the time required to reach the center line temperature of 800 K is

t = 58 sec

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

i think slash and