Answer: Final length = 749.998 ft
Explanation:
We would assume that the coefficient of linear expansion of iron is 36 x 10^- 6/C
We would apply the formula for calculating linear thermal expansion which is expressed as
L1 = aL(θ2 - θ1)
where
L1 = change in length
L = original length
a = coefficient of linear expansion of iron
θ2 = final temperature
θ1 = initial temperature
From the information given,
L = 750
θ2 = - 18
θ1 = 34
a = 12 x 10^- 6/C
By substituting these values into the formula,
L1 = 36 x 10^- 6(- 18 - 34)
L1 = 36 x 10^- 6(- 52)
L1 = - 0.001872
Thus,
Final length - initial length = - 0.001872
Final length - 750 = - 0.001872
Final length = - 0.001872 + 750
Final length = 749.998 ft
