Two steel wires of same length but radii $r$ and $2r$ are connected together end to end and tied to a wall as shown. The force stretches the combination by $10\ mm$ . How far does the midpoint $A$ move ......... $mm$

821-297

  • A

    $2$

  • B

    $4$

  • C

    $6$

  • D

    $8$

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