# Homework Help: Negative vector why isn't it choice 4.

1. Feb 5, 2016

1. The problem statement, all variables and given/known data

If the vector B⃗ has a magnitude of 45.0 m and makes an angle of 60.0 ∘ with the +x axis, the vector -B⃗
choices:
1. has a magnitude of 45.0 m
2. has the same direction as B⃗ , but a magnitude of − 45.0 m
3.makes an angle of − 60.0 ∘ with the +x axis
4. has the opposite direction of B⃗ and a magnitude of − 45.0 m
2. Relevant equations

3. The attempt at a solution
y axises
I -------45.0m diagonal
I 60 Degrees angle
<-(-x)-------------------+x--axises---->
I
I
-y axises

2. Feb 5, 2016

### UncertaintyAjay

What does it mean for magnitude to be negative? Does it make sense for the length of a vector to be negative?

3. Feb 5, 2016

Oh . I see. Thanks you . Magnitude can't be negative
So is it -60 with respect to the x causes because it's now in the third quadrant since the vector b negative is when you reverse the head and the tail of the arrow.

4. Feb 5, 2016

### UncertaintyAjay

It would be -120. Not -60

5. Feb 6, 2016