Chapter 3 - Vectors and Coordinate Systems - Exercises and Problems - Page 82: 5

The y-component of the vector is 6 m

Since the vector is in the first quadrant, the y-component of the vector is positive. Therefore; $x^2+y^2 = (10~m)^2$ $y^2 = (10~m)^2 - x^2$ $y = \sqrt{(10~m)^2 - x^2}$ $y = \sqrt{(10~m)^2 - (8~m)^2}$ $y = 6~m$ The y-component of the vector is 6 m.