CAPE Physics Unit 1 · 2018 · Paper 2 · Question 4(c)(i)
A cylindrical copper wire and a cylindrical steel wire, each 1.5 m long and 2 mm in diameter, are joined to form a 3 m long composite wire. The composite wire is loaded until its length becomes 3.0003 m. Young's modulus for copper = 1.2 × 10¹¹ N m⁻². Young's modulus for steel = 2.0 × 10¹¹ N m⁻².
Calculate the ratio of the strain in the steel wire to the strain in the copper wire.
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