Two blocks of masses 3 kg and 5 kg are connected by a metal wire over a smooth pulley. The breaking stress of the metal is (24/π)×10² N m⁻². Find the minimum wire radius. Take g=10 m s⁻².
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Question

Two blocks of masses 3 kg and 5 kg are connected by a metal wire over a smooth pulley. The breaking stress of the metal is (24/π)×10² N m⁻². Find the minimum wire radius. Take g=10 m s⁻².

G1 Physics · Accepted Answer

Use stress σ=F/A, strain ε=ΔL/L and Young's modulus Y=σ/ε. For a uniform segment, ΔL=FL/(AY); for thermal restraint, thermal strain αΔT produces stress YαΔT. Evaluating the given data/statements gives 12.5 cm. Therefore the correct answer is C.