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A wire elongates by mm when a load W is hanged from it. If the wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be (in mm)

1. 1
2. 2
3. zero
4. 1/2

Correct answer: 1

Solution

When two equal weights are hung from both ends of the wire, the tension in the wire effectively doubles compared to when a single weight is applied. Since elongation is directly proportional to the load, the wire will elongate by the same amount as it did with one weight, resulting in a total elongation of 1 mm.

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