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JEE Main 2026 · 5 Apr · Shift 1, Physics question 43

Two wires as shown in the figure below, made of steel and have breaking stress of 12×10812\times10^8 N/m². Area of cross-section of upper wire is 0.008 cm² and of lower wire is 0.004 cm². The maximum mass that can be added to pan without breaking any wire is ________ kg.
(take g=10g=10 m/s²)

From the ceiling, an upper wire holds a 30 kg block; a lower wire from it holds a 10 kg block, from which a pan hangs.
Choose one option
Answer and worked solution

Official answer: B

Wire strengths.

  • Upper wire: 12×108×0.008×10−4=96012\times10^8\times0.008\times10^{-4}=960 N.
  • Lower wire: 12×108×0.004×10−4=48012\times10^8\times0.004\times10^{-4}=480 N.

Loads (added mass M).

  • Upper wire carries (30+10+M)g≤960(30+10+M)g\le960, so M≤56M\le56 kg.
  • Lower wire carries (10+M)g≤480(10+M)g\le480, so M≤38M\le38 kg.

Maximum: 38 kg.

(B)

Topics:Stress and strain
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