Puppy Pull
1. **Problem Statement:** Juana and Diego pull a stubborn puppy with forces of 23 lb and 27 lb at angles 18° and 15°, respectively. Find the force the puppy exerts to hold them at a standstill, i.e., the resultant force.
2. **Formula and Rules:** The resultant force vector \( \mathbf{R} \) is the vector sum of the two forces:
$$\mathbf{R} = \mathbf{F}_1 + \mathbf{F}_2$$
where each force vector can be expressed in component form:
$$\mathbf{F} = F \langle \cos \theta, \sin \theta \rangle$$
Angles are measured from the positive x-axis (assumed horizontal).
3. **Calculate components of each force:**
- For \( \mathbf{F}_1 \) with magnitude 23 lb and angle 18°:
$$F_{1x} = 23 \cos 18^\circ$$
$$F_{1y} = 23 \sin 18^\circ$$
- For \( \mathbf{F}_2 \) with magnitude 27 lb and angle 15°:
$$F_{2x} = 27 \cos 15^\circ$$
$$F_{2y} = 27 \sin 15^\circ$$
4. **Evaluate components numerically:**
Using approximate values:
$$\cos 18^\circ \approx 0.9511, \sin 18^\circ \approx 0.3090$$
$$\cos 15^\circ \approx 0.9659, \sin 15^\circ \approx 0.2588$$
Calculate:
$$F_{1x} = 23 \times 0.9511 = 21.8753$$
$$F_{1y} = 23 \times 0.3090 = 7.1070$$
$$F_{2x} = 27 \times 0.9659 = 26.0793$$
$$F_{2y} = 27 \times 0.2588 = 6.9876$$
5. **Sum components to find resultant:**
$$R_x = F_{1x} + F_{2x} = 21.8753 + 26.0793 = 47.9546$$
$$R_y = F_{1y} + F_{2y} = 7.1070 + 6.9876 = 14.0946$$
6. **Interpretation:** The puppy pulls with a force equal in magnitude and opposite in direction to \( \mathbf{R} \) to hold the children at a standstill.
**Final answer:**
$$\boxed{\mathbf{R} = \langle 47.95, 14.09 \rangle}$$
This is the component form of the force the puppy exerts.