Q.

A vector has magnitude same as that of A→=3i^+4j^ and is parallel to B→=4i^+3j^. The x and y components of this vector in first quadrant are x and 3 respectively where x= _________ .                    [2024]


Ans.

(4)    Given A→=3i+4j, B→=4i+3j,

         |A|=32+42=5, B^=4i+3j5,B→|B|=B^

         Now, as per question, C→=|A|B^, mag of A→ and direction of B

         =(5)(4i+3j)5=4i+3j,4i+3j,          ∴x=4