Question

Two vectors a and b of magnitudes 2 units and 4 units respectively are shown in the figure. Which of the following mathematical operations is/are correct ?

Answer 1

YOUR ANSWER IS IN THE ATTACHMENT PLZZ REFER TO THE ATTACHMENT

Answer 2

Answer:

(c) $\vec{a} .\vec{b} = 4$ which is the correct answer for the given question

Explanation:

Given, two vector $\vec{a}$ and $\vec{b}$ of magnitudes 2 units and 4 units respectively.

And also given the angle between two vector is  60°.

We know that  formula of dot product of two vector is

                   $\vec{a}.\vec{b}$= $|\vec{a}||\vec{b}|cos\theta$ ..............(i)

So , $|\vec{a}| = 2$ , $|\vec{b}| = 4$  and $\theta = 60$ (Given in the question )

Where $|\vec{a}|$ and $|\vec{b}|$ are the magnitudes of the vectors.

Step 1:

Put the value of $\vec{|a|}$ ,$\vec{|b|}$ and the $\theta$ in equation(i)

∴ $\vec{a}.\vec{b}$ = 2 ×4×cos60°

        = 8 × 1/2 = 4      ( value of cos60° is $\frac{1}{2}$)

Final answer :

Hence , the  option (c) is correct  answer .