Newtonian Motion Mini-book Vocabulary Acceleration— the rate of change of velocity Action/Reaction Pair— a pair of simultaneous equal but opposite forces resulting from the interaction of two objects; the pair of forces do not sum due to their action being on separate bodies Air Resistance—the frictional force caused by air Balanced Force—individual forces that sum to zero Coefficient of Friction—the ratio of the force of friction to the normal force acting between two objects Equilibrium—the state of a body in which there is no change in its motion Fluid Friction—any friction force due to motion in or through a fluid Force—the cause of an acceleration or the change in an object’s motion; notably, a push (pull) that acts upon an object Friction—the resistance that one surface or object encounters when moving over /past another. Fundamental Forces—four forces that act between bodies of matter and that are mediated by one or more particles; The Four Fundamental Forces are: The Strong Nuclear Force, The Weak Nuclear Force, The Electromagnetic Force, and The Gravitational Force. Impulse— for a constant external force, the product of the force and the time over which it acts upon an object Inertia—the tendency of an object to maintain its state of motion; an object’s resistance to a change of its state of motion Kinetic Friction—the frictional force exerted on a moving object Mass—the amount of matter in an object Momentum—a vector quantity defined as the product of an object’s mass and velocity (momentum’s direction is dictated by the velocity’s direction) Net Force—the total force resulting from a vector combination of all external forces on an object; also called the resultant force Normal Force—a contact force exerted by one object on another in a direction perpendicular to the surface of contact Speed—change in distance with respect to time Static Friction—the frictional force exerted on a motionless body by its environment to resist an external force Unbalanced Force—individual forces that do not sum to zero Velocity-change in distance with respect to time with direction; the rate of change of position with respect to a time interval Weight—the magnitude of the force of gravity acting on a object Newton’s 3 Laws of Motion 1. An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force. 2. Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object). 3. For every action there is an equal and opposite re-action. .