# Vector b/a = ?

1. Sep 6, 2007

### Ecterine

The question is: Vector b/a=_____

I guessed a few times (losing a point each time it was wrong) and finally got the answer.

The site (it's online homework) then gave this explanation:

"To the driver of the Audi, the Buick appears to be moving to the left and approaching the Audi at 12 . Recall that if you are driving a car, street signs seem to be coming toward you at the same speed that you are moving with respect to the earth. Notice that "toward you" is opposite to the direction of your motion with respect to the earth."

I'm so confused, this is basically the first homework assignment and I'm already lost. All I can find on google is "you don't divide vectors." The book doesn't have an example, and my teacher didn't go over this.

Why is the answer "12 left""? How do you figure that out?

2. Sep 6, 2007

### learningphysics

I think the question was asked badly... it seems the notation b/a was supposed to mean the velocity of b with respect to a or the velocity of b as seen by a... ie: the velocity of b, in a's frame of reference...

you're right, you can't divide vectors... just seems like poor notation used in the question.

3. Sep 6, 2007

### Ecterine

Thank you... I have a feeling that this class isn't going to go well for me. :/

4. Sep 6, 2007

### Avodyne

I agree with learningphysics; b/a is not standard notation; I've never seen it used before.