Which one of the following is a correct statement ? If `vec P and vec Q` are two non zero vectors of different magnitudes, then

Options

A. `vec P xx vec Q = vec Q xx vec P`
B. `vec P cdot vec Q = -vec Q cdot vec P`
C. `vec P + vec Q = vec Q + vec P`
D. `vec P -vec Q= vec Q - vec P`

Answer

C

Explanation

In the addition of vectors, order of vectors is immaterial.
`therefore vec P + vec Q = vec Q + vec P` is a correct statement.
(c ) is the correct option. Vector addition is commutative but vector subtraction is non-commutative.
Similarly `vec P xx vec Q =- vec Q xx vec P and vec P cdot vec Q = vec Q cdot vec P`
Thus (a) and (b) are wrong.