SASTRA University B. Tech Application Form 2025 – Apply Online @sastra.edu

Geometrical Interpretation of Product of Vectors - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Geometrical Interpretation of Vector product is considered one of the most asked concept.

  • 12 Questions around this concept.

Solve by difficulty

A particle is acted upon by constant forces 4\hat{i}+\hat{j}-3\hat{k}\; and\; 3\hat{i}+\hat{j}-\hat{k}\; which displace it from a point \hat{i}+2\hat{j}+3\hat{k}\; to the point 5\hat{i}+4\hat{j}+\hat{k}\; . The work done in standard units by the forces is given by

Let $\vec{a}=4 \hat{i}+3 \hat{j}+5 \hat{k}$ and $\vec{\beta}=\hat{i}+2 \hat{j}-4 \hat{k}$, Let $\vec{\beta}_1$ be parallel to $\vec{a}$ and $\vec{\beta}_2$ be perpendicular to $\vec{a}$.If $\vec{\beta}=\vec{\beta}_1+\vec{\beta}_2$, then the value of $5 \vec{\beta}_2 \cdot(\hat{i}+\hat{j}+\hat{k})_{\text {is }}$

If \overrightarrow{\mathrm{a}}=\hat{\imath}+2 \hat{k}, \vec{b}=\hat{\imath}+\hat{\jmath}+\hat{k}, \vec{c}=7 \hat{\imath}-3 \hat{\jmath}+4 \hat{k}, \overrightarrow{\mathrm{r}} \times \overrightarrow{\mathrm{b}}+\overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{c}}=\overrightarrow{0} and  \overrightarrow{\mathrm{r}} \cdot \overrightarrow{\mathrm{a}}=0.
Then \vec{r} \cdot \vec{c} is equal to

Let for a triangle ABC,

\begin{aligned} & \overrightarrow{\mathrm{AB}}=-2 \hat{\mathrm{i}}+\hat{\mathrm{j}}+3 \hat{\mathrm{k}} \\ & \overrightarrow{\mathrm{CB}}=\alpha \hat{\mathrm{i}}+\beta \hat{\mathrm{j}}+\gamma \hat{\mathrm{k}} \\ & \overrightarrow{\mathrm{CA}}=4 \hat{\mathrm{i}}+3 \hat{\mathrm{j}}+\delta \hat{\mathrm{k}} \end{aligned}

If  \delta>0 and the area of the triangle  \mathrm{ABC}  is  5 \sqrt{6} , then \overrightarrow{\mathrm{CB}} \cdot \overrightarrow{\mathrm{CA}}  is equal to

Concepts Covered - 1

Geometrical Interpretation of Vector product

Area of Parallelogram

If \vec {\mathbf a} and \vec {\mathbf b}, are two non-zero, non-parallel vectors represented by AD and AB respectively and let Ө be the angle between them.

\\\mathrm{In\;\;\Delta\;ADE,\;\;}\sin\theta=\frac{DE}{AD}\\\Rightarrow \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;DE=AD \sin \theta=|\vec{\mathbf{a}}| \sin \theta\\\text { Area of parallelogram } \mathrm{ABCD}=\mathrm{AB} \cdot \mathrm{DE}\\\text{Thus,}\\\text { Area of parallelogram } \mathrm{ABCD}=|\vec{b} \| \vec{a}| \sin \theta=|\vec{a} \times \vec{b}|

 

Area of Triangle

If \vec {\mathbf a} and \vec {\mathbf b}, are two non-zero, non-parallel vectors represent as the adjacent sides of a triangle then its area is given as \frac{1}{2}\left | \vec {\mathbf a}\times\vec {\mathbf b} \right |

The area of a triangle is ½ (Base) x (Height)

From the figure,

\\\text { Area of triangle } \mathrm{ABC}=\frac{1}{2} \mathrm{AB} \cdot \mathrm{CD}\\\\\text { But } \mathrm{AB}=|\vec{\mathbf b}| \text { (as given), and } \mathrm{CD}=|\vec{\mathbf a}| \sin \theta\\\\\text { Thus, Area of triangle } \mathrm{ABC}=\frac{1}{2}|\vec{\mathbf b}||\vec{\mathbf a}| \sin \theta=\frac{1}{2}|\vec{\mathbf a} \times \vec{\mathbf b}|

 

NOTE:

\\1.\;\;\;\text {The area of a parallelogram with diagonals } \vec{\mathbf{d}}_{1} \text { and } \vec{\mathbf{d}}_{2}\;\;\text{is }\;\frac{1}{2}\left |\vec{\mathbf{d}}_{1}\times \vec{\mathbf{d}}_{2} \right |.\\\\2.\;\;\;\text {The area of a plane quadrilateral } A B C D \text { with AC and BD as diagonal }\\\mathrm{\;\;\;\;\;}\text{ is}\;\;\frac{1}{2}\left | \overrightarrow{\mathbf {AC}}\times \overrightarrow{\mathbf {BD}} \right |.\\\\3.\;\;\;\text{If }\;\vec{\mathbf a},\;\vec{\mathbf b}\;\text{and }\;\vec{\mathbf c}\text { are position vectors of a } \Delta A B C, \text { then its area is}\\\mathrm{\;\;}\mathrm{\;\;\;}\frac{1}{2}\left | (\vec{\mathbf a}\times \vec{\mathbf b})+(\vec{\mathbf b}\times \vec{\mathbf c})+(\vec{\mathbf c}\times \vec{\mathbf a}) \right |.

Study it with Videos

Geometrical Interpretation of Vector product

"Stay in the loop. Receive exam news, study resources, and expert advice!"

Books

Reference Books

Geometrical Interpretation of Vector product

Mathematics for Joint Entrance Examination JEE (Advanced) : Vectors and 3D Geometry

Page No. : 3.22

Line : 12

E-books & Sample Papers

Get Answer to all your questions

Back to top