Question

which of the following is not true ? If `vec(A)=3hat(i)+4hat(j)` and `vec(B)=6hat(i)+8hat(j)` where A and B are the third side of the triangle has length equal to :-
A. `vec(A)xxvec(B)=0`
B. `A/B=(1)/(2)`
C. `vec(A).vec(B)=48`
D. A=5

Answer 1

Correct Answer - C
checking option:`" " vec(A)=3hat(i)+4hat(j)`
`vec(B)=6hat(i)+8hat(j)`
(A)`vec(A)xxvec(B)=24hat(k)-24hat(k)=0`
(B) `(|vec(A)|)/(|vec(B)|)=(5)/(10)=(!)/(2)`
(C) `vec(A).vec(B)=18+32=50`
`vec(A).vec(B)!=48`
(D) `A=5`
Hence (C)