Louie Simmons has made the force equation the most popular of all biomechanical equations: Force = Mass x Acceleration. Fly by night strength coaches use this equation (incorrectly most of the time) to explain everything, which is the main motivation for me to develop content explaining all the other elements of biomechanics that are also important.
Torque = Force x Moment Arm
A great starting point when discussing rotational biomechanics is to explain torque. Torque is the ability of a force to cause rotation on a lever.
Torque is the rotational cousin of the force equation. Torque is the driving force for human movement. Muscles in conjunction with bones, ligaments, and tendons are responsible for movement. Muscles shorten, causing the tendons (a tendon is a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone) to pull on its corresponding bone. This creates a rotational movement around a joint.
An example would be the quad tendon that crosses the knee becoming continuous with the patellar tendon attaching to the tibia. When the quadriceps shorten, they pull on the quadriceps tendon, causing the patellar tendon to pull on the tibia producing knee extension. All locomotion is created by torque at the corresponding joints.