Physics The study of physical forces and qualities: the scientific study of matter, energy, force, and motion, and the way they relate to each other The study of matter, motion, energy and forces.

Displacement The difference between the initial position and the final position of an object that has moved. The process in which an object starts in one place and ends up in another location.

Motion The process of changing position. Changing spots through movement.

Speed The distance an object moves divided by the time it takes to move that distance. The instance where something moves separated by the amount of time it takes to move the distance. Speed= distance divided by time.

Constant Speed When an object moves the same distance over a given unit of time. An object moving at the same speed in one direction.

Changing Speed When the distance an object covers in a unit of time increases or decreases. When a moving object gets faster or slower.

Average Speed You calculate the average speed by dividing the total distance by the total time. Average speed= distance divided by time.

Velocity The speed and the direction of a moving object. How fast and at what angle an object is traveling.

Constant Velocity An object that moves with a constant speed and its direction does not change. Something that always goes at the same speed and same direction.

Changing Velocity Velocity changes when either an object’s speed or direction changes. When an object’s speed or direction changes.

Acceleration The rate of change of velocity per unit of time. A measurement of difference in velocity over a timed period. Going faster or slower or changing direction in a period of time.

Force A push or pull of an object. To push or pull something.

Contact Force A push or pull on an object by another object that is touching it. A force that is applied by touching. Friction is the most common contact force.

Noncontact Force A push or pull an object applies to another object without touching it. A force that is applied to another without you seeing it touch. Gravity and magnetism are the major noncontact forces.

Gravity An attractive force that exists between all objects that have mass. A force that pulls on objects together depending on their distance and mass.

Friction A contact force that resists the sliding of two surfaces that are touching. The resistance that two forces cause or create through touch.

Balanced Forces Forces acting on an object that combine and form a net force of zero. When forces are equal to each other. No movement

Unbalanced Forces Forces acting on an object that combine and form a net force that is not zero. Forces that act on an object that cause motion.

Newton’s First Law of Motion Law of Inertia If the net force on an object is zero then the object’s motion will not change. 8 th Grade Terms An object will keep doing what it is doing. An object in motion will stay in motion until acted upon by another force.

Newton’s Second Law of Motion Law of Acceleration Acceleration = velocity divided by mass 8 th Grade Terms An object’s motion will change in the direction of and proportional to the force acting upon it.

Newton’s Third Law of Motion Law Reaction For every action there is and equal and opposite reaction.