A push or pull on an object

The force two surfaces exert on each other when they rub together

Two solid surfaces slide over each other

Combination of all the forces action on an object

Friction between two objects that aren't moving

A force that pulls objects together

A solid object is moving through a fluid

On object's resistance to chang ein motion

Occurs when the only force action on an object is gravity

Measure if the force of gravity on an object

A characteristic of an object that is related to mass and velocity

In the absence of outside forces the total momentum of objects that interact down not change