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NEET2018PhysicsMathematics in PhysicsActual

The moment of the force, F → = 4 i ^ + 5 j ^ − 6 k ^ at ( 2 , 0 , − 3 ) , about the point ( 2 , − 2 , − 2 ) , is given by

Options

  1. A(-7 i -8 j -4 k )
  2. B(-4 i - j -8 k )
  3. C(-8 i -4 j -7 k )
  4. D(-7 i -4 j -8 k )

Correct answer

D. (-7 i -4 j -8 k )

Step-by-step solution

F → = 4 i ^ + 5 j ^ - 6 k ^ r → = 2 - 2 i ^ + 0 - - 2 j ^ + - 3 - - 2 k ^ = 2 j ^ - 1 k ^ r → × F → = 2 j ^ - 1 k ^ × 4 k ^ + 5 j ^ - 6 k ^ = i ^ j ^ k ^ 0 2 - 1 4 5 - 6 = - 7 i ^ - 4 j ^ - 8 k ^

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