1. **Problem 1: Find vector C such that A + B + C = 0 for each figure.**
**Top-left figure:**
- Vector A has magnitude 4 m and angle 40° above positive x-axis.
- Vector B has magnitude 2 m and angle 20° below positive x-axis.
**Step 1:** Write components of A and B.
$$A_x = 4 \cos 40^\circ, \quad A_y = 4 \sin 40^\circ$$
$$B_x = 2 \cos (-20^\circ), \quad B_y = 2 \sin (-20^\circ)$$
**Step 2:** Calculate numeric values.
$$A_x = 4 \times 0.7660 = 3.064$$
$$A_y = 4 \times 0.6428 = 2.571$$
$$B_x = 2 \times 0.9397 = 1.879$$
$$B_y = 2 \times (-0.3420) = -0.684$$
**Step 3:** Since $A + B + C = 0$, then $C = - (A + B)$.
$$C_x = -(A_x + B_x) = -(3.064 + 1.879) = -4.943$$
$$C_y = -(A_y + B_y) = -(2.571 - 0.684) = -1.887$$
**Answer for top-left:**
$$\boxed{C = (-4.943, -1.887)}$$
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**Top-right figure:**
- Vector A: length 2 m, 15° with negative x-axis vertically upward means angle $180^\circ - 15^\circ = 165^\circ$ from positive x-axis.
- Vector B: length 4 m, 15° above positive x-axis.
**Step 1:** Components:
$$A_x = 2 \cos 165^\circ, \quad A_y = 2 \sin 165^\circ$$
$$B_x = 4 \cos 15^\circ, \quad B_y = 4 \sin 15^\circ$$
**Step 2:** Calculate numeric values.
$$A_x = 2 \times (-0.9659) = -1.932$$
$$A_y = 2 \times 0.2588 = 0.518$$
$$B_x = 4 \times 0.9659 = 3.864$$
$$B_y = 4 \times 0.2588 = 1.035$$
**Step 3:** Find $C$:
$$C_x = -(A_x + B_x) = -(-1.932 + 3.864) = -1.932$$
$$C_y = -(A_y + B_y) = -(0.518 + 1.035) = -1.553$$
**Answer for top-right:**
$$\boxed{C = (-1.932, -1.553)}$$
---
2. **Problem 2: Forces on tilted floor**
- $F_1 = 3.0$ N at $135^\circ$ from horizontal (left upward)
- $F_2 = 6.0$ N vertically upward ($90^\circ$)
- $F_3 = 5.0$ N at $30^\circ$ below horizontal to the right ($-30^\circ$)
Assuming floor is horizontal, components parallel to floor are horizontal components, perpendicular are vertical components.
**Step 1:** Find components of each force.
$$F_{1x} = 3.0 \cos 135^\circ = 3.0 \times (-0.7071) = -2.121$$
$$F_{1y} = 3.0 \sin 135^\circ = 3.0 \times 0.7071 = 2.121$$
$$F_{2x} = 6.0 \cos 90^\circ = 0$$
$$F_{2y} = 6.0 \sin 90^\circ = 6.0$$
$$F_{3x} = 5.0 \cos (-30^\circ) = 5.0 \times 0.8660 = 4.330$$
$$F_{3y} = 5.0 \sin (-30^\circ) = 5.0 \times (-0.5) = -2.5$$
**Step 2:** Sum components for net force.
$$F_{net,x} = F_{1x} + F_{2x} + F_{3x} = -2.121 + 0 + 4.330 = 2.209$$
$$F_{net,y} = F_{1y} + F_{2y} + F_{3y} = 2.121 + 6.0 - 2.5 = 5.621$$
**Step 3:** (a) Component parallel to floor is horizontal component:
$$\boxed{F_{net,\parallel} = 2.209\ \text{N}}$$
(b) Component perpendicular to floor is vertical component:
$$\boxed{F_{net,\perp} = 5.621\ \text{N}}$$
**Step 4:** (c) Magnitude and direction of net force:
$$|F_{net}| = \sqrt{(2.209)^2 + (5.621)^2} = \sqrt{4.878 + 31.601} = \sqrt{36.479} = 6.04$$
Direction angle $\theta$ from horizontal:
$$\theta = \tan^{-1} \left( \frac{5.621}{2.209} \right) = \tan^{-1}(2.545) = 68.5^\circ$$
**Answer:**
$$\boxed{|F_{net}| = 6.04\ \text{N}, \quad \theta = 68.5^\circ \text{ above horizontal}}$$
Vector Sums Adbbcf
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