# What is the |vector A-vector B|

1. Sep 14, 2008

### s31t8n8

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

vector A: ------>
vector B; <----------

choices are:

A) Vector A-vector B
B) A-B
C) Vector B-vector A
D) B-A
E) Vector A + vector B
F) A+B
G) |vector B- Vector A|

2. Sep 14, 2008

### alphysicist

If I'm interpreting everything correctly, then D would be an answer. I do believe there is another true answer; what do you think it is, and why?

3. Sep 15, 2008

### louie3006

well, you have to line vector A on top of vector B and then perform the subtraction and you'll see that the resulting vector would look like :
vector A: ----->
vector B: <----------
<-----

4. Sep 15, 2008

### alphysicist

Right; and how is that resulting vector that you found related to what they are asking for in the problem?

5. Sep 15, 2008

### s31t8n8

im gonna take a guess and say its B. if not could you please explain what the answer is? Thanks

6. Sep 15, 2008

### alphysicist

The answer B is not correct because it would be a negative number; choice B says to subtract the length of $\vec B$ from the length of $\vec A$. Since $\vec A$ is shorter $\vec B$, then choice B is a negative number.

But $|\vec A-\vec B|$ is a magnitude and therefore positive.

For the remember that the quantity you are looking for is a positive number, not a vector, and is the magnitude of the difference of the vectors. (I cannot give out answers here as that would violate forum rules.)

Last edited: Sep 15, 2008