2.Linear transmission of motion

2.1 Levers

A lever is a rigid bar that turns around a point called a fulcrum.
Each force produces a specific torque, which is the force multiplied by its distance from the fulcrum.

                               TORQUE=FORCE x DISTANCE

When the forces acting on opposite ends of a lever are equal, we say the lever is in equilibrium. We can express this mathematically as the Law of the lever.
                   
                                         F x d=R x r

Classes of levers:

We can levers into classes according to the locations of the fulcrum, force, and resistance.

                                            

2.2 Pulleys and compound pulley systems.

In the systems of pulleys, the equilibrium between the forces depends on the path that the the rope  follows.

Pulleys:

 A pulley is a wheel that rotates around an axis and has a groove. If we pull ropes belts or chains through pulleys.

Compound pulley systems

A compound pulley system is a combination of fixed and movable pulleyss. It is also called a block and tackle system. 

Horizontal system

Exponential system

Vertical system