| A | B |
|---|
| Acceleration | Rate of change of velocity, speed up, slowing down, changing direction. |
| Average speed | obtained by dividing total distance by total time. |
| Constant speed | Speed that does not change |
| Deceleration | Negative acceleration, slowing down |
| Distance | The length between two places |
| Force | A push or a pull that gives energy to an object; sometimes causing a change in the motion of the object. |
| Frame of Reference | Background that is assumed to be stationary (not moving) that you compare objects which are assumed to be moving |
| Friction | Force that acts in the opposite direction of motion; will cause an object to slow down and finally stop. |
| Gravity | Force of attraction that depends on the mass of two objects and the distance between them; responsible for accelerating an object toward earth. On earth, acceleration due to gravity 9.8m/s/s. |
| Inertia | Tendency of objects to remain in motion or to stay at rest unless acted upon by an outside force. |
| Law of Conservation of Momentum | Law that states the momentum is always conserved. One object may lose momentum, but the momentum lost by the object is gained by another. |
| Law of Universal Gravitation | Law that states that all objects in the universe attract each other by the force of gravity. |
| Mass | The amount of matter in an object |
| Momentum | Mass of an object times its velocity; determines how difficult it is to stop the object's motion. |
| Motion | Change in position in a certain amount of time. |
| 1st Law of Motion | Called the Law of Inertia: an object at rest will remain at rest and an object in motion will remain in motion unless acted upon by an outside force |
| 2nd Law of Motion | Relationship between force, mass, and acceleration. F=MA |
| 3rd Law of Motion | For every action there is an equal and opposite reaction. |
| Speed | Rate of at which an object moves |
| Velocity | Speed in a given direction |
| Weight | Mass acted on by gravity |
| Balanced Force | when to total forces on an object are equal |
| Net Force | the amount of force that overcomes an opposing force to cause motion; the net force can be zero if the opposing forces are equal. |
| Newton | A unit of force; the abbreviation is N; 1kg X 1m/sec/sec |
| Unbalanced force | when the total force on an object is not zero; unbalanced force changes the motion of an object. |
| Rolling friction | Resistance created when one object rolls over another one. |
| Sliding Friction | Resistance created when two surfaces rub against one another. |
| viscous friction | resistance created by objects moving in water or other fluids |
| Air friction | the opposing force created by objects moving in air |
| Equilibrium | state in which all acting forces is zero; stable, balanced, unchanging. |
