crossword puzzle title

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Across
  1. 2. distance and time
  2. 8. combination of forces acting on object
  3. 11. forces that cause change in motion
  4. 12. moving at steady rate
  5. 13. average speed
  6. 14. a measure how much a mass is
  7. 15. what makes us stay down
  8. 16. A force that opposes motion between two surfaces that are in contact
  9. 17. objects will move until stopped
  10. 18. An object's change in position relative to a reference point
Down
  1. 1. A place or object used for comparison to determine if an object is in motion
  2. 3. the first three letters of the alphabet
  3. 4. A graph with distance on the vertical axis and time on the horizontal axis
  4. 5. a measurement type for force
  5. 6. a push or pull
  6. 7. equal force acting on a object in opposite directions
  7. 9. speed in direction
  8. 10. resistance to motion change
  9. 13. rate velocity changes