Forces - Introduction

Introduction

A forceA physical interaction (pushing or pulling) tending to change the state of motion (velocity) of an object. causes or changes an object's motion: It is a push or pull on an object. Forces have both a size and a direction. Forces also work in pairs: In order for a force to occur there must be an interaction between two objects. For example, when throwing a boomerang a person applies a force to the object that makes it move. Weightlifting exerts a force on the weight to pull it upward. These are forces that occur by physical contact between the two objects.

Yet forces also occur upon a person who is standing still. Forces are, in fact, occurring on everyone and everything on Earth, along with celestial objects. In these forces, two interacting objects exert a push or pull with no physical contact between them. An example of this force is gravityForce of attraction between objects, the strength of which depends on the mass of each object and the distance between them.. Gravity is the force of attraction between any two objects in the universe.