If the vectors vec P = ahat i + ahat j + 3hat | vedclass

Name: PDF Generator App | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

$\overrightarrow{P} \cdot \overrightarrow{Q}=0$
(If $\overrightarrow{\mathrm{P}}$ and $\overrightarrow{\mathrm{Q}}$ are perpendicular to each other)

Vedclass · Accepted Answer

$3$

Vedclass · Answer

$\overrightarrow{P} \cdot \overrightarrow{Q}=0$
(If $\overrightarrow{\mathrm{P}}$ and $\overrightarrow{\mathrm{Q}}$ are perpendicular to each other)
$(a \hat{i}+a \hat{j}+3 \hat{k}) \cdot(a \hat{i}-2 \hat{j}-\hat{k})=0$
$a \cdot a-a \cdot 2-3 \cdot 1=0$
$a^{2}-2 a-3=0$
$a^{2}-3 a+a-3=0$
$(a-3)(a+1)=0$
$a=3$ and $a=-1$

If the vectors $\vec P = a\hat i + a\hat j + 3\hat k$ and $\vec Q = a\hat i - 2\hat j - \hat k$ are perpendicular to each other then the positive value of $a$ is

Similar Questions

If $\vec{A}+\vec{B}+\vec{C}=0$ then $\vec{A} \times \vec{B}$ is ............

The vector sum of two forces is perpendicular to their vector differences. In that case, the force

$ $

Four persons $P, Q, R$ and $S$ are initially at the four corners of a square of side $d$. Each person now moves with a constant speed $v$ in such a way that $P$ always moves directly towards $Q, Q$ towards $R$. $R$ towards $S$, and $S$ towards $P$. The four persons will meet after time ........

${d \over {dx}}\left( {{1 \over {{x^4}\sec x}}} \right) = $