Science
A body of knowledge, often formulated as laws and theories, based on the collection of data through observation and experiment.
Mechanics is the study of force and motion. A mechanism is defined by two forces: the driving force (effort) and the resistant force (load).
Mechanisms consisting of toothed parts that mesh to transmit the rotational motion of the shafts they are a part of.
System consisting of two pulleys with a rope running around them to lift a load. Using two or more pulleys reduces the amount of effort needed.
System consisting of a bar pivoting on a fulcrum to lift a load. The amount of effort required is related to the position of the pivot and the length of the bar.