1. Unit 2- Force and Motion
Vocabulary- Part I

2. A system of objects that are not moving with respect to each other
Frame of Reference
A system of objects that are not moving with respect to each other

3. Movement in relation to a frame of reference
Relative Motion
Movement in relation to a frame of reference

4. Length between two points
Distance
Length between two points

5. Displacement
The position with respect to the origin; the length and direction from the starting point to the ending point.

6. Ratio of the distance traveled to the time the object moves
Speed
Ratio of the distance traveled to the time the object moves

7. The total distance traveled divided by the total time traveled
Average Speed
The total distance traveled divided by the total time traveled

8. The rate at which an object is moving at a given moment in time.
Instantaneous Speed
The rate at which an object is moving at a given moment in time.

9. A description of motion involving both speed and direction.
Velocity
A description of motion involving both speed and direction.

10. Acceleration
The change in velocity. It can occur when speed changes, when direction changes or when both speed and direction changes.

11. The movement of an object toward Earth because of gravity.
Free Fall
The movement of an object toward Earth because of gravity.

12. Constant Acceleration
A steady change in velocity