Answer
The maximum value of the force will be at $\theta=0^{\circ}$ and the minimum value of the force will be at $\theta=90^{\circ}$.
Work Step by Step
From part (a), we have: $F=\dfrac{0.6 W \times (\cos \theta)}{\sin 12^{\circ}}$.
The magnitude of the force varies with cosine $\theta$. Therefore, the maximum value of the force will be at $\theta=0^{\circ}$, and the minimum value of the force will be at $\theta=90^{\circ}$.