Let a , b , c be three vectors such that | a |= 3 , | b |=5, b c =10 and the angle between b and c is 3 . If a is perpendicular to the vector b c , then | a ( b c )| is equal to

Step-by-step solution

aligned & b c =10 & | b || c | 3 =10 & (5)| c | ( 1 2 )=10 & | c |=4 aligned aligned & | a ( b c )|=| a || b c | 2 & =| a || b c | & =| a || b || c | 3 & =( 3 )(5)(4) ( 3 2 ) & =30 aligned