# Homework Help: Magnitude of the vector r=r2−r1?

1. Jan 29, 2010

### Shardooni

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

Consider the two vectors r1 and r2 . The magnitudes of the two vectors are: r1=5.9 and r2=8.5. The vectors directions relative to the x axis are defined by the angles: θ1=37 degrees and θ2=65 degrees.

What is the magnitude of the vector r=r2−r1?

What is the angle between r and the x axis? (in degrees)

2. Relevant equations
Break each vector into components: x1, y1, x2, y2, then consider the vector r as (x2-x1,y2-y1)

3. The attempt at a solution

Break each vector into components: x1, y1, x2, y2, then consider the vector r as (x2-x1,y2-y1)

So broke each vector into triangles and calculated the x-component & y= components:
R1 x component: tan37deg=3.55/x= 4.73 N
R1 y component: sin37deg= y1/5.9=3.55 N
R2 x component: tan65=7.7/x=3.59
R2 y component: sin65=y2/8.5

then i got stuck here... help me out please?

Last edited: Jan 29, 2010
2. Jan 29, 2010

### ideasrule

Now that you have x1, y1, x2, and y2, why can't you write the vector as (x2-x1,y2-y1)?