Vocabulary

3. friction between moving surfaces
5. stated laws that describe the effects of forces on motion
7. measurement of an objects motion
9. friction between objects that results in "no motion"
13. force that makes motion more difficult between two materials that are in contact
14. explains that an objects motion at a constant speed maintains that speed unless another force acts on it
15. total distance traveled divided by the total time of travel
16. forces that are equal in size and in opposite direction
17. force of attraction between objects
20. a force acting on an object causes the object to speed up in the direction of the force

1. describes the speed and the direction of an object
2. speed of motion at any given moment
4. when one object pushes on the second object, the second one pushes back on the first with a force that is equal in size and opposite in direction
6. when an object changes position
8. push or pull one object exerts on another
10. speed that does not change
11. measures when things speed of or slow down
12. combination of all forces acting on an object
18. an object resists any change in its motion
19. measurement of the force that gravity pulls on an object