Coefficient of linear expansion (K-1 ): Brass (2E-5), Copper (1.7E-5), Steel (1.
ID: 1327278 • Letter: C
Question
Coefficient of linear expansion (K-1 ): Brass (2E-5), Copper (1.7E-5), Steel (1.2E-5)
Coefficient of Volume expansion (K-1 ): Brass (6E-5), Copper (5.1E-5), Steel (3.6E-5)
Problems:
1) Text (17.21) A machinist bores a hole of diameter 1.35 cm. in a steel plate at a temperature of 25.0 o C. What is the cross sectional area of the hole (a) at 25 o C, and (b) when the temperature of the plate is increased by 175 o C? Assume the coefficient of linear expansion remains constant over this temperature range.
T (C) 50 40 20 F 10 0 , (min) 1 23 4Explanation / Answer
1. Cross-sectional area = pi x (1.35/2)^2 cm^2 = 1.431 cm^2
2) Let a be the coefficient of linear expansion.
Hence, coefficient of areal expansion = 2a
New cross-sectional area
= 1.431[1+ 2a(175-25.0)] cm^2
= 1.43(1+300*1.2 * 10 ^ -5 ) ===== 1.435148 cm2