1. Feb 27, 2009

### ymehuuh

Vector A has a magnitude of 7.90 units and makes an angle of 43.0° counter-clockwise from the positive x-axis. Vector B has a magnitude of 8.00 units and is directed along the negative x-axis.

(a) Find the vector sum vector A + vector B .
Magnitude of vector A + vector B = ? units
Direction of vector A + vector B : ?° counterclockwise from +x-axis

(b) Find the vector difference vector A - vector B .
Magnitude of vector A - vector B : ? units
Direction of vector A - vector B : ?° counterclockwise from +x-axis

My attempt:
Ok, so I find the x and y components of vector A and B which is....
Ax=7.9 cos 43 = 5.778
Ay=7.9 sin 43 = 5.388

Bx=-8
By= 0

Now...I'm not sure what to do next?

2. Feb 27, 2009

### LowlyPion

Welcome to PF.

Add the x,y components together to get the components of your result in part a).

Make Vector components of B negative and then add the components together as before for part b).

To figure magnitudes
|Vector|2 = = X-component2 + Y-component2

To figure angle Y-Component/X-component = tanθ
(Make a drawing to be sure you have the angle in the correct quadrant.)

3. Feb 27, 2009

### ymehuuh

Got it. Awesome. Thanks.