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The linear velocity of rotating body is ...

The linear velocity of rotating body is given by `vecv = vecomega xx vecr` where `vecomega` is the angular velocity and `vecr` is the radius vector. The angular velocity of body `vecomega = hati - 2hatj + 2hatk` and this radius vector `vecr = 4hatj - 3hatk`, then `|vecv|` is

A

`sqrt(29)` units

B

`sqrt(31)` units

C

`sqrt(37)` units

D

`sqrt(41)` units

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The correct Answer is:
To solve the problem, we need to find the magnitude of the linear velocity vector \(\vec{v}\) given by the cross product of the angular velocity vector \(\vec{\omega}\) and the radius vector \(\vec{r}\). ### Step-by-Step Solution: 1. **Identify the vectors:** - The angular velocity vector is given as: \[ \vec{\omega} = \hat{i} - 2\hat{j} + 2\hat{k} \] - The radius vector is given as: \[ \vec{r} = 4\hat{j} - 3\hat{k} \] 2. **Write the radius vector in full form:** - Since there is no \(\hat{i}\) component in \(\vec{r}\), we can represent it as: \[ \vec{r} = 0\hat{i} + 4\hat{j} - 3\hat{k} \] 3. **Calculate the cross product \(\vec{v} = \vec{\omega} \times \vec{r}\):** - We can set up the determinant to calculate the cross product: \[ \vec{v} = \begin{vmatrix} \hat{i} & \hat{j} & \hat{k} \\ 1 & -2 & 2 \\ 0 & 4 & -3 \end{vmatrix} \] 4. **Calculate the determinant:** - Expanding the determinant: \[ \vec{v} = \hat{i} \begin{vmatrix} -2 & 2 \\ 4 & -3 \end{vmatrix} - \hat{j} \begin{vmatrix} 1 & 2 \\ 0 & -3 \end{vmatrix} + \hat{k} \begin{vmatrix} 1 & -2 \\ 0 & 4 \end{vmatrix} \] - Calculating each of the 2x2 determinants: - For \(\hat{i}\): \[ (-2)(-3) - (2)(4) = 6 - 8 = -2 \] - For \(\hat{j}\): \[ (1)(-3) - (2)(0) = -3 - 0 = -3 \] - For \(\hat{k}\): \[ (1)(4) - (-2)(0) = 4 - 0 = 4 \] - Putting it all together: \[ \vec{v} = -2\hat{i} + 3\hat{j} + 4\hat{k} \] 5. **Calculate the magnitude of \(\vec{v}\):** - The magnitude \(|\vec{v}|\) is given by: \[ |\vec{v}| = \sqrt{(-2)^2 + (3)^2 + (4)^2} \] - Calculating each term: \[ |\vec{v}| = \sqrt{4 + 9 + 16} = \sqrt{29} \] 6. **Final Result:** - Therefore, the magnitude of the linear velocity vector is: \[ |\vec{v}| = \sqrt{29} \]

To solve the problem, we need to find the magnitude of the linear velocity vector \(\vec{v}\) given by the cross product of the angular velocity vector \(\vec{\omega}\) and the radius vector \(\vec{r}\). ### Step-by-Step Solution: 1. **Identify the vectors:** - The angular velocity vector is given as: \[ \vec{\omega} = \hat{i} - 2\hat{j} + 2\hat{k} ...
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ICSE-COMPETITION CARE UNIT-VECTORS AND SCALARS [Selected from Previoius Years Engg. & Med. & IIT Exam Qns]
  1. Two vectors of equal magnitudes having a sum of resultant equal to eit...

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  2. The angle between veca xx vecb and vecb xx veca is

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  3. If the sum of two unit vectors is a unit vector, then the magnitude of...

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  4. If hatn is a unit vector in the direction of the vector vecA, then

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  5. If vec(A)=vec(B)+vec(C ), and the magnitudes of vec(A),vec(B),vec(C ) ...

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  6. The maximum number of components into which a vector can be resolved i...

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  7. The minimum number of vectors of equal magnitude needed to produce zer...

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  8. Given that veca + vecb = veca-vecb,. This can be true when

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  9. If veca * vecb = |veca xx vecb|, then this angle between veca and vecb...

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  10. The projection vector of veca" on "vecb is

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  11. The angle between two vectors veca and vecb is pi//2. Then |hata xx ha...

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  12. Given that veca * vecb = 0 and veca xx vecc = 0 Then the angle between...

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  13. There are n coplanar vectors each of magnitude m and each vector is in...

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  14. Given that veca and vecb are two non zero vectors, then the value of (...

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  15. The linear velocity of rotating body is given by vecv = vecomega xx ve...

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  16. The position vectors os a particle is r=(acosomegat)hati+(asinomegat)h...

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  17. The length of the sum of the vectors veca = 3hati and b = 4hatj is

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  18. If 0.5hati + 0.8hatj + chatk is aunit vector then c is

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  19. The resultant of three vectors 1,2, and 3 units whose directions are t...

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  20. If the angle between the vector vecA and vecB is theta , the value of ...

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