1. Problem 5: Find the direction of vector $C = 2A - B$ where $A = 12i - 16j$ and $B = -24i + 10j$.
2. Use the formula for vector operations: $$C = 2A - B = 2(12i - 16j) - (-24i + 10j)$$
3. Calculate $2A$: $$2A = 24i - 32j$$
4. Calculate $-B$: $$-B = 24i - 10j$$
5. Add $2A$ and $-B$: $$C = (24i - 32j) + (24i - 10j) = (24 + 24)i + (-32 - 10)j = 48i - 42j$$
6. The direction angle $\theta$ of vector $C$ with respect to the positive $x$-axis is given by: $$\theta = \tan^{-1}\left(\frac{y}{x}\right) = \tan^{-1}\left(\frac{-42}{48}\right)$$
7. Calculate the angle: $$\theta = \tan^{-1}(-0.875) \approx -41.19^\circ$$
8. Since the angle is negative, it means $41.19^\circ$ below the positive $x$-axis (east). The direction of $C$ is $41.19^\circ$ south of east.
9. Problem 6: A camel walks 25 km in a direction $30^\circ$ south of west, then 30 km north. Find the distance between the two oases.
10. Represent the first displacement vector $\vec{d_1}$: magnitude 25 km, direction $30^\circ$ south of west.
11. Break $\vec{d_1}$ into components:
$$d_{1x} = 25 \cos(180^\circ - 30^\circ) = 25 \cos 150^\circ = 25 \times (-0.866) = -21.65$$
$$d_{1y} = 25 \sin 150^\circ = 25 \times 0.5 = 12.5$$
Note: Since direction is south of west, $y$ component should be negative, so correct $d_{1y} = -12.5$ km.
12. The second displacement vector $\vec{d_2}$ is 30 km north, so:
$$d_{2x} = 0$$
$$d_{2y} = 30$$
13. Total displacement vector $\vec{D} = \vec{d_1} + \vec{d_2}$:
$$D_x = -21.65 + 0 = -21.65$$
$$D_y = -12.5 + 30 = 17.5$$
14. Distance between oases is magnitude of $\vec{D}$:
$$D = \sqrt{(-21.65)^2 + (17.5)^2} = \sqrt{469.22 + 306.25} = \sqrt{775.47} \approx 27.84$$ km
15. Final answers:
- Direction of $C$ is approximately $41.19^\circ$ south of east.
- Distance between the two oases is approximately 27.84 km.
Vector Direction Distance
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.