An aluminium strut in a satellite frame is long

PHYSICS · Multi-part · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Lattice dynamics and thermal properties of solids · Lattice dynamics and thermal properties of solids

Condensed Matter Physics, Ch Thermal expansion and lattice thermal conductivity

Problem

An aluminium strut in a satellite frame is 2.5 m2.5\,\mathrm{m} long. As the satellite moves between sunlight and shadow the strut swings through a temperature range of 80 K80\,\mathrm{K}. Aluminium has γG=2.17\gamma_G = 2.17, a molar heat capacity CV=24.2 J mol−1K−1C_V = 24.2\,\mathrm{J\,mol^{-1}K^{-1}} close to 3R3R, a bulk modulus Bmod=76 GPaB_{\rm mod} = 76\,\mathrm{GPa} and a molar volume Vm=9.99×10−6 m3 mol−1V_m = 9.99\times10^{-6}\,\mathrm{m^3\,mol^{-1}}. ((a)) Predict aluminium's linear expansion coefficient with the Gruneisen relation. ((b)) Use it to find how much the strut's length changes over the 80 K80\,\mathrm{K} swing.

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