# Vector question

1. Mar 26, 2009

### vorcil

1. Find a.b given the following information
|a|=3

two vectors a.b are perpendicular to eachother

b
|
|
|
|__________a

3. |a| = 3
a = squareroot of 3,

if B is a vector perpendicular to a,
dunno what to do from here,

2. Mar 26, 2009

### djeitnstine

3. Mar 26, 2009

### vorcil

the a.b,

the dot product

4. Mar 26, 2009

### Staff: Mentor

One definition for the dot product is
a $\cdot$ b = |a||b| cos($\theta$)
where $\theta$ is the angle between the vectors.