Question

Given r1=3mi+4mj.dertemine the magnitude and direction angles of the position vector

Answer 1

$$\vec r=(3\hat i+4\hat j)\:\rm m$$

The magnitude

$$r=\sqrt{3^2+4^2}=5\;\rm m$$

The direction angles

$$\alpha=\cos^{-1}\frac{3}{5}=53^\circ$$

$$\beta=\cos^{-1}\frac{4}{5}=37^\circ$$