Final answer:
The length of the moment arm of the force, rm, can be found using the equation rm = l sin(θ) in terms of l and θ.
Step-by-step explanation:
The length of the moment arm of the force, rm, can be found in terms of l and θ using the equation:
rm = l sin(θ)
Here, l is the distance from the pivot point to the point where the force is applied, and θ is the angle between the force vector and the lever arm. The moment arm represents the perpendicular distance between the pivot point and the line along which the force acts.