Question: Determine the magnitude and the coordinate direction angles of the resultant force
Set $F_1=75+z_1$ N, $F_2=55+z_2$ N, $\theta_1=30+z_3$ degree and $\theta_2=60+z_4$ degree (and $d = 1+0.1z_1$ unit)
1. **State the problem:**
We need to find the magnitude and coordinate direction angles of the resultant force vector $\mathbf{F}_R = \mathbf{F}_1 + \mathbf{F}_2$ where $F_1 = 75+z_1$ N, $F_2 = 55+z_2$ N, $\theta_1 = 30+z_3$ degrees, $\theta_2 = 60+z_4$ degrees, and $d = 1+0.1z_1$ units.
2. **Understand the vectors:**
$\mathbf{F}_1$ points up-left and $\mathbf{F}_2$ points down-right from the origin with given angles $\theta_1$ and $\theta_2$ relative to reference lines.
3. **Express forces in components:**
Assuming the coordinate system with axes $x$, $y$, and $z$ as described:
- $\mathbf{F}_1$ components:
- $F_{1x} = -F_1 \cos(\theta_1)$ (left direction)
- $F_{1y} = 0$ (no y component given)
- $F_{1z} = F_1 \sin(\theta_1)$ (upward)
- $\mathbf{F}_2$ components:
- $F_{2x} = F_2 \cos(\theta_2)$ (right direction)
- $F_{2y} = 0$ (no y component given)
- $F_{2z} = -F_2 \sin(\theta_2)$ (downward)
4. **Calculate resultant components:**
$$
F_{Rx} = F_{1x} + F_{2x} = -F_1 \cos(\theta_1) + F_2 \cos(\theta_2)
$$
$$
F_{Ry} = 0 + 0 = 0
$$
$$
F_{Rz} = F_1 \sin(\theta_1) - F_2 \sin(\theta_2)
$$
5. **Calculate magnitude of resultant force:**
$$
F_R = \sqrt{F_{Rx}^2 + F_{Ry}^2 + F_{Rz}^2} = \sqrt{\left(-F_1 \cos(\theta_1) + F_2 \cos(\theta_2)\right)^2 + 0 + \left(F_1 \sin(\theta_1) - F_2 \sin(\theta_2)\right)^2}
$$
6. **Calculate coordinate direction angles:**
The angles between $\mathbf{F}_R$ and the axes are given by:
$$
\alpha = \cos^{-1}\left(\frac{F_{Rx}}{F_R}\right) \quad \text{(angle with x-axis)}
$$
$$
\beta = \cos^{-1}\left(\frac{F_{Ry}}{F_R}\right) \quad \text{(angle with y-axis)}
$$
$$
\gamma = \cos^{-1}\left(\frac{F_{Rz}}{F_R}\right) \quad \text{(angle with z-axis)}
$$
7. **Important notes:**
- Angles should be converted to degrees if using radians.
- Angles must be between $-180$ and $180$ degrees.
- Use $\cancel{...}$ to show canceled terms if simplifying fractions (not applicable here).
8. **Summary:**
- Calculate $F_1$, $F_2$, $\theta_1$, $\theta_2$, and $d$ from given expressions.
- Compute components $F_{Rx}$, $F_{Ry}$, $F_{Rz}$.
- Find magnitude $F_R$.
- Find angles $\alpha$, $\beta$, $\gamma$.
This completes the solution steps for the first question.