Two persons pull a wire towards themselves. Each person exerts a force of 200 N on the wire. Young's modulus of the material of the wire is 1×10¹¹ N m⁻². The original length of the wire is 2 m and the area of cross section is 2 cm². The wire will extend in length by μm.

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20. Idea: two people pulling opposite ends with 200 N each put a tension of 200 N in the wire, not 400 N — the forces balance, they do not add. Given: F=200 N, L=2 m, A=2 cm²=2×10⁻⁴ m², Y=1×10¹¹ N m⁻². Δ l=(FL)/(AY)=(200×2)/((2×10⁻⁴)(1×10¹¹)). Δ l=(400)/(2×10⁷)=2×10⁻⁵ m=20 μm.

Two persons pull a wire towards themselves. Each person exerts a force of 200 N on the wire. Young's modulus of the material of the wire is 1×10¹¹ N m⁻². The original length of the wire is 2 m and the area of cross section is 2 cm². The wire will extend in length by ______ μm.

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