# Force

## Gravity

1. The force that attracts a body toward the center of the earth, or toward any other physical body having mass. For most purposes Newton's laws of gravity apply, with minor modifications to take the general theory of relativity into account.

## Friction

The resistance that one surface or object encounters when moving over another

## Electrical

The strength of an electric field at a given point in space near an electrically charged object is proportional to the amount of charge on the object, and inversely proportional to the distance between the point and the object. See also electromagnetism, electrostatic force.

## Air Resistance

The force acts in the opposite direction to an object moving through the air

## Buoyancy

the ability or tendency to float in water or air or some other fluid

## Tension/Elastic

A force caused by a string, spring, or rope resulting in stretching or pulling.

## Normal

the force perpendicular to an object's surface that results in support

## contact

those that require the agent that causes the force to be in contact with object

## noncontact

those that act at a distance