Coefficient of linear expansion (K-1 ): Brass (2E-5), Copper (1.7E-5), Steel (1.
ID: 1327279 • 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.
Explanation / Answer
A )
We know,
Cross Sectional Area A = * d ^2 / 4
A°= 3.14 * 1.35 ^2 / 4 = 1.430 cm2
B)
We know,
A = A° ( 1 + 2 t )
steel = 1.2 * 10^-5 / °C
A = 1.430 ( 1 + 2 * 1.2 * 10^-5 * 175 )
A = 1.430 ( 1 + 0.0042 )
A = 1.436 cm2