Two forces with equal magnitudes $F$ act on a body and the magnitude of the resultant force is $F/3$. The angle between the two forces is

  • A

    ${\cos ^{ - 1}}\left( { - \frac{{17}}{{18}}} \right)$

  • B

    ${\cos ^{ - 1}}\left( { - \frac{1}{3}} \right)$

  • C

    ${\cos ^{ - 1}}\left( {\frac{2}{3}} \right)$

  • D

    ${\cos ^{ - 1}}\left( {\frac{8}{9}} \right)$

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  • [NEET 2016]