# Vector component question

1. Jan 26, 2012

### Allenman

This question was just given on a CEE 270 exam (handwritten by professor). The way it's written doesn't make any sense to me.

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

A force vector
$\vec{F}$ = ($70.0 \hat{i} + F_{y} \hat{j} + 140.0 \hat{k}$ ) N​

has a component of +20.0 N in the direction defined by the vector
$\vec{P}$ = ($6 \hat{i} - 3 \hat{j} - 2 \hat{k}$ ) kN​

Solve for $F_{y}$.

3. The attempt at a solution

I asked the professor if I needed to rotate the coordinate system as the question states that a component of $\vec{F}$ is in the $\vec{P}$ direction. He said no rotation of the coordinate system should be needed.

I am very confused at how to even approach this problem. Please help. Does it even make sense?

2. Jan 26, 2012

### Staff: Mentor

The problem makes sense. When you want to know the projection of one vector onto another, what vector operation comes to mind?

3. Jan 26, 2012

### Allenman

Wow... I didn't recognize it as a vector projection problem.... Thank you!