A vertical steel beam 4.0 m tall, mass 200 kg, carries a load of 2.0 × 1 0 5 N . Its temperature falls by 5. 0 ∘ C . c = 460 J / ( kg K ) , α = 12 × 1 0 − 6 per °C. Find the change in internal energy

Question

A vertical steel beam 4.0 m tall, mass 200 kg, carries a load of 2.0 × 1 0 5 N . Its temperature falls by 5. 0 ∘ C . c = 460 J / ( kg K ) , α = 12 × 1 0 − 6 per °C. Find the change in internal energy in J (three significant figures).

TestHub · Accepted Answer

Heat lost = 200 ( 460 ) ( − 5 ) = − 460000 J . Contraction = 4 ( 12 × 1 0 − 6 ) ( 5 ) = 2.4 × 1 0 − 4 m ; load does work 2 × 1 0 5 ( 2.4 × 1 0 − 4 ) = 48 J on the beam. Δ U = − 459952 J ≈ − 4.60 × 1 0 5 J .

Physics - Heat & Thermo Question with Solution | TestHub

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