The Force and Related Concepts

Force Can you define it? Definition: The cause of acceleration, or the change in an object’s velocity (or the push or pull on an object) How can velocity change? Many forces can act on an object at once. The combination of all these forces is called… Net Force

Balanced and Unbalanced Balanced Forces All forces on the object combine for a net force of zero Balanced forces do not change the object’s motion The object can be moving, but there is no change Unbalanced Forces Forces acting on the object combine to produce a nonzero net force All the forces combine to act like a single force on the object Motion is affected by an unbalanced force

Friction What is friction? Definition: A force between two objects that are in contact that opposes the motion of either object Friction happens as long as there is… contact

Friction Frictional force varies with surface Air Resistance Examples A form of friction between a moving object and air molecules Depends on the size and shape of the object

Gravity What is gravity? Definition: Gravity does not require contact The force of attraction between two particles Gravity does not require contact Affected by mass and distance Not a one-way street