What Is The Resultant Vector? Can someone please, please, please help me. I really don’t get this.

Question

Two vectors act on a point a shown below. What is the resultant vector?

^ |

\ 7 |

\ |

30° \ |

—————————

|

| 3

V

|

|

(A) 5∠210°

(B) 8.889∠-47.02°

(C) 6.083∠175.24°

(D) 7.616∠210°

(E) None of these.

I had gotten (E) but got it wrong. Can someone please help me understand this?!

Also, this was kind of hard to do, i couldn’t find a way to ask the question. So I “drew” what it looked like. So, I get if you have no idea what this is.

Answer 1

Use the Law of Cosines

||v||² = 3² + 7² - 2(3)(7)(cos 120°)

Can you solve for v and answer?