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The angles with a vector hat(i)+hat(j)+s...

The angles with a vector `hat(i)+hat(j)+sqrt(2hat(k))` makes with X,Y and Z axes respectively are

A

`60^(@),60^(@),60^(@)`

B

`45^(@), 45^(@), 45^(@)`

C

`60^(@), 60^(@),45^(@)`

D

`45^(@), 45^(@), 60^(@)`

Text Solution

AI Generated Solution

The correct Answer is:
To find the angles that the vector \( \hat{i} + \hat{j} + \sqrt{2} \hat{k} \) makes with the X, Y, and Z axes, we can use the concept of the dot product and the magnitudes of the vectors involved. ### Step-by-Step Solution: 1. **Define the Vector**: The given vector is \[ \mathbf{A} = \hat{i} + \hat{j} + \sqrt{2} \hat{k} \] 2. **Find the Magnitude of the Vector**: The magnitude of vector \( \mathbf{A} \) is calculated as follows: \[ |\mathbf{A}| = \sqrt{(1)^2 + (1)^2 + (\sqrt{2})^2} = \sqrt{1 + 1 + 2} = \sqrt{4} = 2 \] 3. **Calculate the Angle with the X-axis**: Let \( \alpha \) be the angle with the X-axis. We use the dot product: \[ \cos(\alpha) = \frac{\mathbf{A} \cdot \hat{i}}{|\mathbf{A}| |\hat{i}|} \] Here, \( \hat{i} \) has a magnitude of 1, and the dot product \( \mathbf{A} \cdot \hat{i} = 1 \). Thus, \[ \cos(\alpha) = \frac{1}{2} \implies \alpha = \cos^{-1}\left(\frac{1}{2}\right) = 60^\circ \] 4. **Calculate the Angle with the Y-axis**: Let \( \beta \) be the angle with the Y-axis. Similarly, \[ \cos(\beta) = \frac{\mathbf{A} \cdot \hat{j}}{|\mathbf{A}| |\hat{j}|} \] The dot product \( \mathbf{A} \cdot \hat{j} = 1 \). Thus, \[ \cos(\beta) = \frac{1}{2} \implies \beta = \cos^{-1}\left(\frac{1}{2}\right) = 60^\circ \] 5. **Calculate the Angle with the Z-axis**: Let \( \gamma \) be the angle with the Z-axis. We find: \[ \cos(\gamma) = \frac{\mathbf{A} \cdot \hat{k}}{|\mathbf{A}| |\hat{k}|} \] The dot product \( \mathbf{A} \cdot \hat{k} = \sqrt{2} \). Thus, \[ \cos(\gamma) = \frac{\sqrt{2}}{2} \implies \gamma = \cos^{-1}\left(\frac{\sqrt{2}}{2}\right) = 45^\circ \] 6. **Final Angles**: Therefore, the angles that the vector makes with the X, Y, and Z axes are: \[ \alpha = 60^\circ, \quad \beta = 60^\circ, \quad \gamma = 45^\circ \] ### Summary of Results: - Angle with X-axis (\( \alpha \)): \( 60^\circ \) - Angle with Y-axis (\( \beta \)): \( 60^\circ \) - Angle with Z-axis (\( \gamma \)): \( 45^\circ \)

To find the angles that the vector \( \hat{i} + \hat{j} + \sqrt{2} \hat{k} \) makes with the X, Y, and Z axes, we can use the concept of the dot product and the magnitudes of the vectors involved. ### Step-by-Step Solution: 1. **Define the Vector**: The given vector is \[ \mathbf{A} = \hat{i} + \hat{j} + \sqrt{2} \hat{k} ...
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A2Z-VECTORS-Dot Product
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  9. If a vector vec(P) making angles alpha, beta, gamma respectively with ...

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  12. If for two vectors vec(A) and vec(B), sum (vec(A)+vec(B)) is perpendic...

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