Question

If vec A and vec B are vectors and vec B = -vec A , which of the following is true ?

a) The magnitude of is equal to the negative of the vec B magnitude of vec A

b) Ā and vec B are perpendicular .

c) The direction angle of is equal to the direction angle of vec B A plus 180 degrees

d ) vec A + vec B =2 vec A .

Answer 1

If A + B = C for the vector equation then substituting for B gives

A + (-A) = C = 0

The only thing that can be said about "C" is that it has zero magnitude.