If a unit vector is represented as $\overrightarrow{\mathrm{u}}=0 \cdot 4 \hat{\imath}+0 \cdot 7…
If a unit vector is represented as $\overrightarrow{\mathrm{u}}=0 \cdot 4 \hat{\imath}+0 \cdot 7 \hat{\jmath}+\mathrm{c} \hat{k}$, then the value of ' $\mathrm{c}$ ' is
$\sqrt{0 \cdot 11}$
$\sqrt{0 \cdot 25}$
$\sqrt{0 \cdot 65}$
$\sqrt{0 \cdot 35}$
Solution
$\sqrt{0.4^{2}+0.7^{2}+c^{2}}=1$
Thus, $\mathrm{c}^{2}=1-0.65=0.35$, or $\mathrm{c}=\sqrt{0.35}$
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