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The vector in the direction of the vector 2i^−j^−2k^2\hat{i} - \hat{j} - 2\hat{k} that has magnitude 9 units is:

Solution

✅ Correct Option: 4

The vector 2i^−j^−2k^2\hat{i} - \hat{j} - 2\hat{k} has the desired direction. To find a vector in the same direction with magnitude 9 units, the original vector needs to be scaled appropriately.

The magnitude of 2i^−j^−2k^2\hat{i} - \hat{j} - 2\hat{k} is:

∣vector∣=(2)2+(−1)2+(−2)2|\text{vector}| = \sqrt{(2)^2 + (-1)^2 + (-2)^2}

=4+1+4= \sqrt{4 + 1 + 4}

=9= \sqrt{9}

=3= 3 units


To scale the vector to magnitude 9 units, multiply by the ratio of desired magnitude to current magnitude:

Scaling factor =93=3= \frac{9}{3} = 3

Required vector =3(2i^−j^−2k^)= 3(2\hat{i} - \hat{j} - 2\hat{k})

=6i^−3j^−6k^= 6\hat{i} - 3\hat{j} - 6\hat{k}


Therefore, the vector in the direction of 2i^−j^−2k^2\hat{i} - \hat{j} - 2\hat{k} with magnitude 9 units is 6i^−3j^−6k^6\hat{i} - 3\hat{j} - 6\hat{k}.

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