Final answer:
The movement factor in economic diagrams such as the demand curve is price, and it is located on the vertical axis.
Step-by-step explanation:
In economic diagrams like the demand curve, the movement factor is typically price, and it is located on the vertical axis. On a demand curve, when all other economic factors are held constant, under the assumption of ceteris paribus, the relationship between the quantity demanded and the price is depicted, with quantity on the horizontal axis and price on the vertical axis. This concept is foundational in understanding how markets operate, enabling analysis of how changes in price impact the quantity demanded.