If `vecA=2hati+4hatj` and `vecB=6hati+8hatj` and A and B are the magnitudes of `vecA` and `vecB`, then which of the following is not true?

Options

A. `vecAxx vecB= vec0`
B. `(A)/(B) = (1)/(2)`
C. `vecA*vecB= 48`
D. `A= 5`

Answer

3

Explanation

`vecA= 3hati+4hatj, vecB= 6hati+8hatj`
`vecAxx vecB= |{:(hati,,hatj,,hatk),(3,,4,,0), (6,,8,,0):}| = 0hati+ 0hatj+ 0hatk=vec0`
`A= sqrt(3^(2)+ 4^(2))= 5 & B =sqrt(6^(2)+ 8^(2))= 10`
`vecA*vecB= (3hati+4hatj)*(6hati+8hatj) = 18+ 32 =50`