Answer:
The moment of a force (also known as torque) is calculated as the product of the force applied and the perpendicular distance from the pivot point to the line of action of the force. In this case, the force \( F \) is applied at an angle \(\theta\) with the vertical line.
To find the perpendicular distance, we use the component of the length \( L \) that is perpendicular to the force. Since the force is at an angle \(\theta\) with the vertical, the perpendicular distance is \( L \sin(\theta) \).
The moment of force \( \tau \) is given by:
\[ \tau = F \times L \sin(\theta) \]
Therefore, the correct answer is:
(D) \( LF \sin(\theta) \)