Question

CLASS 11 WALA PHODO IS QUESTION KO !! ✌​

Answer 1

Vector A is written as a.

Answer:

Option C.

Explanation:

Here,

Resultant of vector A and vector B is is equal to vector A and vector B.

Magnitude of vector A = a = magnitude of vector B.

Here, if C is the angle between them :

= > | A + B | = a

= > | A + A | = a

= > √( a² + a² + 2a.a.cosC ) = a

= > √( 2a² + 2a²cosC ) = a

= > a√( 2 + 2cosC ) = a

= > √( 2 + 2cosC ) = 1

= > 2 + 2cosC = 1

= > 2cosC = 1 - 2 = - 1

= > cosC = - 1 / 2

= > cosC = cos120°

Hence angle-measure of the angle between vector A and vector B is 120°.