consider the vector F1: (27N,20°)The angles are measured from the positive x axis with the counter-clockwise angular direction taken as positive.

Question

Consider the vector:F2=-F1

What is in degrees as measured from the positive x in the counter-clockwise angular direction the direction of vector F2?

*I have tried using the formula arctan (y/x)+ 180 but it keeps telling me I am incorrect. I would love it if anyone could give me some guidance on this.

Answer 1

F1 = 27N[20o] = 27*cos20 + i27*sin20 =
25.37 + 9.23i.

F2 = -27N[20o] = -27*cos20 - 27*sin20 =
-25.37 - -9.23i

Tan Ar = Y/X = -9.23/-25.37 = 0.36382
Ar = 20o = Reference Angle.
Since X and Y are both negative, we are in the 3rd Quad.

A = 20 + 180 = 200o = The direction of
F2.