Adding and substracting vectors???

Question

A - B + C = ?

they all start from the origin

they are not connected besides the orgin

A = 44, 28 degrees east of south

B = 26.5, 56 degrees west of south

C = 31, 270 degree south

the final product is like the letter Y.

i get how to add and subtract 2 vectors but how do u do it with 3 vectors? My book doesnt show how...

Answer 1

Since you know how to do two vectors, just start by figuring out A-B.  Then once you have that new vector add C.  That will give you A-B+C.  You could also start by adding -B+C then adding A since vector addition is associative.

Answer 2

ok we got it!

x-axis means east

hint:  I'm rotating Counterclockwise

sum the x components:

44* Cos( 28)+ 26.5* Cos( 304)+ 31* Cos( 270) =53.668

sum the y components:

44* Sin( 28)+ 26.5* Sin( 304)+ 31* Sin( 270) =-32.313

Angle with the positive x-axis: =328.95 degrees

vector magnitude 62.64

The -B points B in the opposite direction

angle 270+(90-56)=270+34=304 degrees

The problem: this post says:

B = 26.5, 56 degrees west of south

Your drawing shows 56 degrees "north of west"