99.
(a) A change of five Celsius degrees is equivalent to a change of nine Fahrenheit degrees. Using Table 19-
2,
α =
23
× 10
−6
/C
◦
5 C
9 F
= 13
/F
.
(b) For ∆T = 55 F
and L = 6.0 m,we find ∆L = Lα∆T = 0.0042 m.