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If A = 2i + 2j-k, B = 6i-3j+2k, then A ...

If `A = 2i + 2j-k, B = 6i-3j+2k, ` then `A xx B` will be given by

A

`2i-2j-k`

B

`6i-3j+2k`

C

`i-10j-18k`

D

`i+j+k`

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The correct Answer is:
To find the cross product of the vectors \( A \) and \( B \), we will follow these steps: ### Step 1: Write down the vectors Given: \[ A = 2i + 2j - k \] \[ B = 6i - 3j + 2k \] ### Step 2: Set up the determinant for the cross product The cross product \( A \times B \) can be calculated using the determinant of a matrix formed by the unit vectors \( i, j, k \) and the components of vectors \( A \) and \( B \): \[ A \times B = \begin{vmatrix} i & j & k \\ 2 & 2 & -1 \\ 6 & -3 & 2 \end{vmatrix} \] ### Step 3: Calculate the determinant To calculate the determinant, we expand it as follows: \[ A \times B = i \begin{vmatrix} 2 & -1 \\ -3 & 2 \end{vmatrix} - j \begin{vmatrix} 2 & -1 \\ 6 & 2 \end{vmatrix} + k \begin{vmatrix} 2 & 2 \\ 6 & -3 \end{vmatrix} \] ### Step 4: Calculate each of the 2x2 determinants 1. For the \( i \) component: \[ \begin{vmatrix} 2 & -1 \\ -3 & 2 \end{vmatrix} = (2)(2) - (-1)(-3) = 4 - 3 = 1 \] 2. For the \( j \) component: \[ \begin{vmatrix} 2 & -1 \\ 6 & 2 \end{vmatrix} = (2)(2) - (-1)(6) = 4 + 6 = 10 \] 3. For the \( k \) component: \[ \begin{vmatrix} 2 & 2 \\ 6 & -3 \end{vmatrix} = (2)(-3) - (2)(6) = -6 - 12 = -18 \] ### Step 5: Combine the components Now substituting back into our expression for \( A \times B \): \[ A \times B = 1i - 10j - 18k \] ### Final Result Thus, the cross product \( A \times B \) is: \[ A \times B = i - 10j - 18k \]
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ML KHANNA-ADDITION AND MULTIPLICATION OF VECTORS -Self Assessment Test (MULTIPLE CHOICE QUESTIONS)
  1. If a and b are position vectors of A and B respectively the position v...

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  2. a and b are the position vectors of the points A and B with respect to...

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  3. If A = 2i + 2j-k, B = 6i-3j+2k, then A xx B will be given by

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  4. The number of vectors of unit length perpendicular to vectors vec ...

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  5. A vector a has components 2p and 1 with respect to a rectangular cart...

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  6. If |vecalpha + vecbeta| = |vecalpha - vecbeta|, then

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  7. If veca and vecb are two vectors such that veca.vecb = 0 and veca xx v...

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  8. Let veca, vecb, vecc be three non-coplanar vectors and vecp,vecq,vecr ...

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  9. The components of a vector veca along and perpendicular to a non-zero ...

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  10. For any three vectors a, b, c (a-b).{(b-c) xx (c-a)} = 2a.(bxxc). ...

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  11. If a = 4i + 6j and b = 3j+4k, then the vector form of component of a a...

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  12. A unit vector perpendicular to the vector 4i-j+3k and -2i+j-2k is

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  13. The unit vector perpendicular to the two vectors i-j and i+2j, and per...

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  14. If u = i xx (a xx i), + j xx (a xx j) + k xx(a xx k), then

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  15. The volume of a parallelopiped whose sides are given by vecOA =2i-3j,v...

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  16. If alpha = 2i + 3j - k, beta = -i + 2j-4k, gamma = i+j+k then the valu...

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  17. Let vec a=2 hat i- hat j+ hat k , vec b= hat i+2 hat j= hat ka n d ve...

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  18. If the vectors vec c , vec a=x hat i+y hat j+z hat ka n d vec b= hat ...

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  19. If veca lies in the plane of vectors vecb and vecc, then which of the ...

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  20. If a xx b = c, b xx c = a and a, b,c be moduli of the vectors a, b,c...

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