Chapter 12 - Section 12.2 - Vectors - 12.2 Exercises - Page 806: 34

True course: $N70.4^oE$ Ground speed: $267km/h$

$a_x=50\cos(45^o)=-35.355$ $a_y=50\sin(45^o)=35.355$ $b_x=250\cos(60^o)=125$ $b_y=250\sin(60^o)=216.506$ $c_x=a_x+b_x=-35.355+125=89.645$ $c_y=a_x+b_x=35.355+216.506=251.861$ $\theta=\arctan(\frac{251.861}{89.645})=70.4^o$ $|c|=\sqrt{89.645^2+251.861^2}=267km/h$