The resultant of two vectors A and B is C . If the magnitude of B is doubled, the new resultant vector becomes perpendicular to A . Then the magnitude of C is

Step-by-step solution

According to the question, A+B=C . .(0) Also, when B is doubled, C becomes perpendicular to A . Let the new magnitude of C be C^ That means A . C^ =0 (A C^ 90=0 )>(A)(A+2 B)=0 .(1)> (A^ 2+2 A B )=0>|A|=-2 A B To find the magnitude of C , square eq. (0) >(A+B)^ 2=|C|>|A|+|B|+2 A B but 2 A B=-|A| . from (1) which means |C|=|B|