MediumPhysicsNewton's Laws of Motion
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A steel rod of length 25 cm has a cross-sectional area of 0.8 cm². The force required to stretch this rod by the same amount as the expansion produced by heating it through 100°C (α = 10⁻⁵ °C⁻¹, Young's modulus of steel = 2 × 10¹¹ N/m²) is:
A
40 N
B
80 N
C
120 N
D
160 N
Explanation
F = γA = γAα Δ T
= 2 × 10 × (0.8 × 10-4 ) ×10-5 × 10 N = 160 N
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