A pushing or pulling action that can make objects speed up or slow down, change direction, or change shape: Tom had to use a lot of force to hammer the nail into the wall.

The Earth's gravitational force pulls down objects so they don't just fly off into space!.

The force that is required to keep an object moving around a circular path: Centripetal force is directed towards the center of the circle. In the absence of this effect, the object would move in a straight line tangential to the circle or keep going in a straight line.

Cars need aid or assistance going around corners, so objects tend to travel in straight lines unless centripetal force bends their motion around into a curve.

A reference to the forces that act parallel to the earth's surface and which produce the folded and faulted geological structures seen in mountain areas.

In geology, folds (curvatures in layered rocks) are generally associated with sedimentary rocks, those that usually have horizontal layers.

The forces which move electric currents around circuits; for example, generators produce electromotive forces.

1. The minimum distance to which a large satellite can approach its primary body without being torn apart by such forces: The tidal forces of the Moon on the Earth's oceans or seas are closest to and farthest from the Moon. 2. The force arising from differences in the strength of gravity experienced over different parts of an object: Such a tidal force is responsible for the tides, and for the breakup of a body straying within the Roche limit of a planet.