This section is from the book "The Engineer's And Mechanic's Encyclopaedia", by Luke Hebert. Also available from Amazon: Engineer's And Mechanic's Encyclopaedia.
Impact, in Mechanics, the simple or single action of one body upon another, to put the latter, if at rest, in motion; or, if it be moving, to increase, retard, or alter the direction of its motion. The point against which the impelling body acts is called the point of impact.
 
Continue to: