a steel beam is 12.0 m long when installed at 23 degrees celsius.Find the change in the beam's length if the temperature changes from -32.0 degrees celcius to 55 degrees celcius?

Answer 1

Cooling from 23ºC to -32ºC
ΔL1= α•L•ΔT1 =12•12•10^-3•[23-(-32)]=
=12•12•10^-3•55= 7.92•10^-3 m
Heating from 23ºC to +55ºC
ΔL2= α•L•ΔT2 =12•12•10^-3•[55-23]=
=12•12•10^-3•32= 4.61•10^-3 m
Chamge in the beam’s length is
ΔL=ΔL1+ ΔL2=7.92•10^-3+ 4.61•10^-3=
=1.253•10^-2 m.