## College Physics (4th Edition)

We can use an equation to find the magnitude of the sum of two vectors A and B: $\vert A+B \vert = \sqrt{\vert A \vert^2+\vert B \vert^2+2~\vert A \vert\vert B \vert~cos(\theta)}$ $\vert A+B \vert = \sqrt{\vert 4.0 \vert^2+\vert 6.0 \vert^2+2~\vert 4.0 \vert\vert 6.0 \vert~cos(60.0^{\circ})}$ $\vert A+B \vert = 8.7$ The magnitude of A+B is 8.7 units.