15. Copper wire section S = 8 mm2 under a tensile force extended by as much as it is lengthened by heating at 30 K. Taking copper Young's modulus E = 118 GPa and a coefficient of linear expansion α = 1.7 • 10-5 K -1, to determine the numerical value of this force.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)