Impetus

noun

A driving force; impulse
(Physics) The force that causes a body or object to move
Increased activity in response to a stimulus

Usage

Impetus commonly refers to the impelling force that spurs an action or decision. Therefore, it is often used to describe the cause or starting point of an event. It can be the direct reason for an action, or it can be a motion to release a chain of events. Depending on the subject of action, impetus can hold a positive or negative connotation. For example, if one is speaking of the cause of a war the usage of impetus will likely invoke adverse feelings, whereas if the impetus results in a beneficial change of habits it will invoke favorable thoughts.

In physics, the Theory of Impetus was once used to explain the changes in velocity of objects in projectile motion. The theory first appeared in the sixth century from John Philoponus as a modified version of Aristotle's theory of motion. Nur ad-Din al-Bitruji elaborated on Philoponus's ideas towards the close of the twelfth century, and his work was edited further by Jean Buridan in the fourteenth century. The theory stated that objects in motion possessed a quality called "impetus" (similar to the modern concept of momentum) that escalated at the same rate as velocity. Buridan supposed that impetus would naturally persist unless acted upon by an outside source of resistance, such as gravity or air. Today, impetus is only rarely used in physics to describe a force that allows a moving body to maintain its velocity as it moves against a form of resistance. Although the Theory of Impetus has been rendered obsolete, the ideas of Buridan and others are still considered notable for their influence on the work of Galileo and Newton.

Example: One girl's community service project became the widespread impetus of the neighborhood to participate in more charitable acts.

Example: Throwing the bowling ball is the impetus that causes the pins to fall over.

Example: Although the boy threw the ball as hard as he could, its lack of further impetus made it bound to hit the floor.

Origin

The first example of impetus is found in the beginning of the fifteenth century, though in Middle English it was spelled as impetous (meaning "a rush or rapid movement"). Impetus, with its modern spelling, can be traced back to the middle of the seventeenth century; the first recorded use of impetus occurred in 1641. Similar to many scientific terms, the word finds its roots in Latin. It is derived from the term impetere, translating to "assault force," "to attack," or "passion." The prefix in- means "toward" or "against" and -petere means "seek" or "to fall upon." As impetus is a driving force, the prefix of "toward" and the body of "seek" clearly mirror its modern definition and use. The translations of "rush" and "against" correlate to the scientific use of impetus (relating to its interaction with gravity and how motion goes against gravity).

Literary Reference:

From Mark Hodders's The Curious Case of the Clockwork Man:

But maybe efficiency isn't all it's held up to be. Maybe it's the inefficiencies and mistakes that give us the best impetus to change and grow and improve.

Here, impetus refers to the motivation needed to progress. According to the author, perhaps inefficiencies are the driving force—or impetus—of change.

Mnemonic

Impetus impairs impediment

References

Theory of Impetus. Wikipedia

Bring out the linguist in you! What is your own interpretation of impetus. Did you use impetus in a game? Provide an example sentence or a literary quote.