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Find the torque of a force F=-3hat(i)+2h...

Find the torque of a force `F=-3hat(i)+2hat(j)+hat(k)` acting at the point `r=8hat(i)+2hat(j)+3hat(k),(iftau=rxxF)`

A

`14hat(i)-38hat(j)+16hat(k)`

B

`4hat(i)+4hat(j)+6hat(k)`

C

`-14hat(i)+38hat(j)-16hat(k)`

D

`-4hat(i)-17hat(j)+22hat(k)`

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The correct Answer is:
To find the torque \(\tau\) of the force \(\mathbf{F} = -3\hat{i} + 2\hat{j} + \hat{k}\) acting at the point \(\mathbf{r} = 8\hat{i} + 2\hat{j} + 3\hat{k}\), we will use the formula for torque given by: \[ \tau = \mathbf{r} \times \mathbf{F} \] ### Step 1: Write down the vectors We have: - \(\mathbf{F} = -3\hat{i} + 2\hat{j} + \hat{k}\) - \(\mathbf{r} = 8\hat{i} + 2\hat{j} + 3\hat{k}\) ### Step 2: Set up the cross product To find the cross product \(\mathbf{r} \times \mathbf{F}\), we can use the determinant of a matrix: \[ \tau = \begin{vmatrix} \hat{i} & \hat{j} & \hat{k} \\ 8 & 2 & 3 \\ -3 & 2 & 1 \end{vmatrix} \] ### Step 3: Calculate the determinant We will expand this determinant using the first row: \[ \tau = \hat{i} \begin{vmatrix} 2 & 3 \\ 2 & 1 \end{vmatrix} - \hat{j} \begin{vmatrix} 8 & 3 \\ -3 & 1 \end{vmatrix} + \hat{k} \begin{vmatrix} 8 & 2 \\ -3 & 2 \end{vmatrix} \] Calculating each of the 2x2 determinants: 1. For \(\hat{i}\): \[ \begin{vmatrix} 2 & 3 \\ 2 & 1 \end{vmatrix} = (2 \cdot 1) - (3 \cdot 2) = 2 - 6 = -4 \] 2. For \(\hat{j}\): \[ \begin{vmatrix} 8 & 3 \\ -3 & 1 \end{vmatrix} = (8 \cdot 1) - (3 \cdot -3) = 8 + 9 = 17 \] 3. For \(\hat{k}\): \[ \begin{vmatrix} 8 & 2 \\ -3 & 2 \end{vmatrix} = (8 \cdot 2) - (2 \cdot -3) = 16 + 6 = 22 \] ### Step 4: Combine the results Putting it all together, we have: \[ \tau = -4\hat{i} - 17\hat{j} + 22\hat{k} \] Thus, the torque \(\tau\) is: \[ \tau = -4\hat{i} - 17\hat{j} + 22\hat{k} \] ### Final Answer The torque of the force is: \[ \tau = -4\hat{i} - 17\hat{j} + 22\hat{k} \] ---

To find the torque \(\tau\) of the force \(\mathbf{F} = -3\hat{i} + 2\hat{j} + \hat{k}\) acting at the point \(\mathbf{r} = 8\hat{i} + 2\hat{j} + 3\hat{k}\), we will use the formula for torque given by: \[ \tau = \mathbf{r} \times \mathbf{F} \] ### Step 1: Write down the vectors We have: ...
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MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS-SCALARS AND VECTORS -Exercise 1
  1. A=2hat(i)+hat(j),B+3hat(j)-hat(k)and C=6hat(i)-2hat(k) Value of A-2B+3...

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  2. if P+Q+P-Q ,then

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  3. What vector must be added to the sum of two vectors 2hat(i)-hat(j)+3ha...

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  4. If |A|=2 and |B|=4 and angle between then is 60^(@) then |A-B|

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  5. If A and B are two vectors such that |A+B|=2|A-B|. The angle between v...

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  6. At what angle should the two forces 2P and sqrt(2P) and Psqrt(2)P act...

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  7. Three forces acting on a boby are shown in the figure. To have the re...

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  8. Three vector A,B and C satisfy the relation A.B=0 and A. C =0. Then t...

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  9. what is the dot product of two vectors of magnitudes 3 and 5,if angle ...

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  10. When A.B =-|A||B|, then

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  11. The condition (a.b)^(2)=a^(2)b^(2) is satisfied when

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  12. The modulus of the vector product of two vectors is (1)/(sqrt(30)) tim...

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  13. In a clockwise system,

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  14. If |AxxB| = sqrt3 A.B, then the value of |A+B| is

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  15. If |A|=2,|B|=5 and |AxxB|=8. Angle between A and B is acute, then (A....

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  16. Find the torque of a force F=-3hat(i)+2hat(j)+hat(k) acting at the po...

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  17. What is the unit vector perpendicular to the following Vector 2hat(i)+...

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  18. If AxxB=BxxA then the angle between A and B is

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  19. What is the value of linear velocity, if vec(omega) = 3hat(i)-4 hat(j)...

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  20. The area of the parallenlogram determined by two adjacentt sides as A=...

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