What components determines the direction of moment?

The direction of a moment, often referred to as torque in a physics context, is determined by two main factors: the force applied and the position vector (also known as the moment arm or lever arm) from the pivot point to the point where the force is applied.

1. **Force Applied**: The magnitude of the force contributes to the magnitude of the moment but its direction (which way the force is applied) combined with the position vector determines the direction of the moment. In simple terms, a clockwise or counterclockwise direction is established based on the orientation of the force relative to the pivot point.

2. **Position Vector**: The distance and direction from the pivot point (or axis of rotation) to the point of force application also significantly influence the moment's direction. The position vector is perpendicular to the direction of the force to calculate the moment.

The direction of the moment follows the right-hand rule. To use the right-hand rule, point your fingers in the direction of the position vector (from the pivot to the point of force application) and curl them in the direction of the force; your thumb then points in the direction of the moment. If the thumb points away from you, it's considered a positive or counterclockwise moment. If it points towards you, it's a negative or clockwise moment.

Now, mathematically, the moment (or torque) is calculated as a cross product of the position vector (\( \vec{r} \)) and the force vector (\( \vec{F} \)), denoted as \( \vec{\tau} = \vec{r} \times \vec{F} \). The right-hand rule can also be used to determine the direction of the cross product, hence the direction of the moment.